Below is a list of commonly used equipment and its purpose.

Natural vs Artificial Seawater

One decision that marine aquarist need to make is whether to use natural seawater (NSW) or artificial seawater (ASW). Marine aquaria can be successful using either so the decision usually comes down to availability, cost and convenience.

When you look at the marine aquarium hobby in Europe and North America, it is obvious that the majority of hobbyists use artificial seawater. This is mostly due to the fact that majority of hobbyists do not live near the coast. And those that do are unlikely to have access to clean natural seawater. In Australia, the situation is very different. The majority of Australians live on, or near, the coast and can either collect their own seawater, buy it from their local fish store or have it delivered.
For those that live inland, natural seawater generally isn’t an option, unless they are prepared to make regular trips to the coast.

Natural seawater is almost always cheaper than ASW. If you are collecting your own, the only real cost is petrol. Although there will be some initial setup cost for containers, pumps or other collecting equipment. If you were to collect around 600 litres in one trip and used around $25 in fuel, the cost is around $0.04 per litre. Of course, if the trip is shorter, or you can collect more water, the cost is even less.
The cost to get NSW delivered varies from $0.08 to $0.12 per litre. Like collecting yourself, there will be some up front costs, such as a storage tank. But that is quickly written off.
NSW from the LFS ranges in cost between $0.10 and $0.20 per litre, depending on the LFS and how much you buy. To this you have to add the cost of petrol to drive to and from the LFS and this may add up to $0.10 per litre depending on how much it carried in each trip and the distance to the LFS.
For artificial seawater, you have to factor in the cost of the salt mix and the freshwater used. Salt mixes can cost anywhere from $0.20 to $1.00 per litre depending on the quantity purchased and the delivery costs. The cost of the freshwater will vary. Even if aged tap water is being used, there is cost associated, but if some form of water purification is used, this will increase the cost.

Having NSW delivered is probably the most convenient assuming you have adequate room for storage of the water. Basically, you just have to be home when it is delivered and the water is ready to be used, immediately.
The next most convenient method is probably going to be mixing ASW. You don’t need to drive anyway and all you have to do is add some salt to freshwater and mix. It is ready to be used within a few hours and little effort is required.
Picking up NSW from the local fish store requires you to drive to the store, have the drums filled, bring them home and unload. This may take anywhere from 30 minutes to a couple of hours and has to be done while the store is open.
Finally, probably the least convenient method is to collect your own NSW. You require your own collection gear and you can spend anywhere up to an hour or more just collecting the water. Add to that the trip to the water, the trip home and the unloading of the drums. The water should also be collected just before high tide when the water conditions are suitable.
Of course, depending on your location, the relative convenience of the options above may change. For example, if you live at or near a clean beach, collecting your own water may actually be easier (or at least more practical) than the other options.

Up until now, the discussion has been deciding between NSW and ASW based on availability, cost and convenience with the assumption that NSW and ASW are on par with respect to chemistry.
It must be said that clean NSW has a lot of benefits over ASW with respect to chemistry. ASW is only an approximation of the concentrations of the various consitituants of seawater. Some elements and compounds are below that of NSW, with others much higher. While generally the variations are inconsequential, the long term effects are not really known. Some elements or compounds may accumulate over time. Although it would be expected that each water change would dilute anything that was building up. With each water change with NSW, you would be bringing the water back to something that resembles NSW. With ASW, you would still only be approximating NSW.
One advantage of ASW in this respect is purity. While the chemistry may not be perfect, if mixed with RO, DI or RO/DI water, you know the water will not have any impurities, other than what was in the salt mix. With NSW, you could be picking up pollution, as well as some organisms such as algal spores. While generally this isn’t a problem, there is a very small element of risk.

Overall, NSW will be a better option if it is available because it will generally be cheaper, and the inconvenience is not all that great.

Activated carbon is used to remove dissolved organic compounds, most typically exhibited by the yellow tint often seen in aquarium water. The tint comes from organic pigments which are products of bacterial decomposition of organic matter within the system.

Activated carbon can also be used to remove heavy metals from the water, such as copper and iron, and acts as a second stage (first stage is particle filter) for reverse osmosis and deionisation filtration of tap water (to remove chlorine/chloramine).

It is important that water is actually forced to flow through the activated carbon media. Simply placing a bag in the side of the sump will work to some degree, but poorly. Typical ways of using it include:

  • chemical media column
  • chemical media bag in sump or where outlet of protein skimmer flow onto it (good for removing ozone if used in the skimmer)

The media only stays active and of any real use for a couple of weeks, at the most. By that time, it will be covered in a biofilm, so absorption is greatly reduced, if not essentially halted.

A bottle trap is a simple alternative to commercial aquarium traps. It is used to capture small crustaceans, such as mantis shrimp, crabs and even hermit crabs.

Bottle traps are made from two water or soft drink bottles. The top of both bottles are used as the two end caps, while the main waist section from one bottle makes the body of the trap. The trap is assembled by simply pushing the two end caps into the trap body, a few small incisions around the wide end of each end cap will make this easier. Holes drilled in the body section will allow water exchange from within the trap and the scent from a small piece of bait to penetrate into the aquarium water to attract the target. Lightly sanding the trap entrance will make it easier for the crustaceans to climb into the trap. A small stone to weight the trap will be required, plus length of fishing line can be used to lower to trap into place and retrieve it.

These fittings are used to get water through the side or base of a tank. They are essentially just a large plastic bolt and nut, with a hole down the middle of the bolt.  If these are sourcing from a plumbing store, then do not ask for a “bulkhead” as they will not know what you are referring to. They will refer to them as Tank Fittings or Tank Outlets.
Bulkheads are typically used in conjunction with or to form the following, all which require water to pass through the side or base of a tank: 

  • Weir and/or Overflow
  • Standpipe
  • Closed Loop

They are designed so that the female section of the fitting goes on the inside of the tank, best, least likely to leak configuration.

Calcium reactors are used to add calcium and carbonate (which adds to the alkalinity) to tank water by means of dissolving calcium carbonate eg coral skeletons. They do this by using carbon dioxide mixed with tank water in a sealed chamber to lower the pH of the water to a level where the skeletons/media dissolves. This water is then dripped back into the tank boosted with calcium and alkalinity.
There are various designs from the simple DIY to fully controlled super expensive.


The calcium reactor has to contain a substrate of calcium carbonate to act as the source of calcium and alkalinity(carbonate).
Suitable materials to utilise are:

  • coral sand
  • crushed coral
  • marble
  • commercial calcium
  • reactor substrates (which are simply coral sand).

The thing to be careful with substrates is that they actually contain only calcium carbonate with trace amounts of other things. If it has high levels of phosphate, then that will add considerable amounts of that into the system. For this reason, oyster shells are a bad thing to be used, but most coral sands are OK.

Do I need a calcium reactor?

If you keep clams and stony corals, and have trouble keeping up with the calcium carbonate demand by using kalkwasser then you need a calcium reactor. Alternatively, it is a lazy mans device for adding calcium carbonate, and if you travel a bit it can be very handy to have.

How do I plumb in a calcium reactor?

For the Korralins, setting up properly entails using either a feed from the return or a siphon from the weir to drive water into the unit. Then use the outlet that comes out of the top as the outlet – prevents any bubbles from forming – rather than the aufgang.

How do I tune a calcium reactor?

Tuning is often confusing to those new to calcium reactors. The objective is basically to ensure the effluent has a good amount of calcium carbonate. In order to dissolve the calcium carbonate the pH of the effluent has to be at least 6.9 for reactor media, or 6.7 or lower for crushed marble. The effluent pH is essentially a measure of the chamber pH which needs to be low enough to dissolve the media. This is achieved by a balance of carbon dioxide going in, and the effluent drip rate. A good starting point for many reactors is roughly 1 bubble every ten seconds, and a drop a second of effluent. This can obviously be scaled up to suit needs. A second chamber can be added for greater efficiency and increasing the effluent pH before being added back into the system.

A small refrigerating unit which pumps tank water through it to keep tank temperatures down in warmer climates.

Following the manufacturers instructions for flow rates chiller can be plumbed inline between a return pump and the display tank, placed between a canister filter and the display tank on the return line or using a dedicated pump a closed loop from sump to sump through the chiller can be used. After installation it is advised to check that actual flow rate achieved matches the manufactures specifications. It is advised to pass filtered water through a chiller as chillers can become blocked by passing unfiltered water through them.

A closed loop is a method of circulating water around an aquarium that uses a pump external to the display tank. Water is taken up through an inlet, passes through the pump, then is returned back into the tank (possibly through multiple outlets). Water current switching devices, such as the Ocean Motions 4 way unit shown below, can be used to alternate the flow between outlets, which creates a more random flow pattern which can be beneficial for hard corals such as Acropora sp.
The benefits of a closed loop system are if it is done with careful planning the inlets and outlets can be hidden within the rock structure, helping to form an aesthetically pleasing display tank without the clutter of pumps / powerheads. When coupled with a current switching device, there is the benefit of alternating flow. This can sometimes be difficult to achieve in the same manner with powerheads.
The problems are, it can be more difficult to clean and maintain the pumps. However, careful planning and installation of double union valves can make it much easier to isolate sections of plumbing or the pump in order to clean them.

Reverse osmosis is a method of water purification where water under pressure is forced through a semi-permeable membrane. The water molecules are small enough to pass through the holes in the membrane, however dissolved salts and other impurities are not. The output is two streams from the RO filter, a purified water stream and a waste stream that contains the impurities at a higher concentration than the input stream.
Typical household units produce around 2-4 litres of wastewater for every litre of purified water. The waste water can be used for washing clothes or watering plants, but can be quite wasteful if it is discarded to the drain in areas where water restrictions apply.
There are various membranes available, although TFC or Thin Film Composite membranes appear to be the most appropriate for aquarium applications, and are capable of reducing contaminants to very low levels of Total Dissolved Solids (TDS).
RO filters will normally utilise pre-filters to remove fine particulate solids, and carbon filters to remove chlorine prior to entering the RO stage in order to extend the life of the membrane. They can also be used with a final deionisation column, with such a system referred to as an RO/DI. This allows much lower levels of contaminants to be reached.

Deionisation is a method of water purification, entailing the use of canisters or columns of resin beads which are capable of removing dissolved ionic species from the feed water. Two resins are used – one (cationic resin) to attract and remove positive ions (cations) and another (anionic resin) to remove negative ions (anions). The two resins may be contained seperatly or may be blended into a mixed bed resin. The benefit of seperating the resins is that they may be regenerated once they are exhausted to enable the resins to be reused. DI filters do not produce any waste water while operating, unlike reverse osmosis (RO) and purify 100% of the water that passes through them.

Eggcrate is more commonly known as Light Diffuser outside of the marine aquaria hobby. It’s intended use is in fluorescent lighting fittings in the ceilings of office buildings. Therefore, can be purchased from electrical wholesalers and / or larger hardware stores.
The most common and cheapest colour available is white. It can also be found in black (and even silver), but this is more expensive and difficult to find a source.


  • Barrier to stop fish going over an overflow.
  • Barrier over the top of a tank to stop fish jumping out or something getting in.
  • Platform to stack liverock on.
  • Stands for frag plugs

Epoxy putty is of great use in the aquarium for mounting coral frags and stabilizing rockwork whilst aquascaping.

The putty comes as a co-extruded malleable stick with two dissimilar components constituting the base putty and a curing catalyst. When ready for use, an appropriately sized portion of the stick can be kneaded to blend the two putty components which triggers the curing process. It takes several hours for the putty to cure to full hardness, during which time it can be shaped and squashed as required. After hardening, it can be drilled and sanded. After a period in the aquarium, the surface of the epoxy will readily become colonised by encrusting algae, corals and other sessile invertebrates. If you constantly dip your hands and the putty in the tank water whilst kneeding, it will make it a lot easier to handle and not stick to your hands.

It must be noted that epoxy putty is not an adhesive as such. It will not “stick” to surfaces, it is a putty or filler. It can be used to form a physical bond between coral frags and rocks, but only if there is sufficient shape or texture to the surfaces that the putty can key into once it has hardened.
Epoxy can be used in combination with supa glue to form physical shapes into which frags or objects can then be glued securely.
The only real adverse reaction that has been noted from use of epoxy putty in the aquarium is that for a short time whilst curing it has been known to cause protein skimmers to produce copious amounts of skimmate. Precautions should be taken to make sure that the skimmer does not cause an overflow event.

There are a number of brands specifically marketed for aquarium use. Other brands are available from hardware stores that have been used successfully by many aquarists. Make sure you get a grade that is labelled as suitable for curing underwater. Proven brands include Selley’s Aqua Kneadit and Bostik.

Filter wool can be a handy thing to have around with a marine aquarium. Its good at collecting undesirable particulate matter out of the water column, which is handy if you have a spawning incident, sandstorm, or something sucked through a powerhead.

However like any form of mechanical filtration (other than protein skimmers) there are negatives to regular use. There are many free swimming beneficial organisms in the aquarium such as ‘pods, larvae etc. which can not only be detrivores, but can provide a food source for corals and fish. Trapping these in filter wool or some other form of mechanical filtration can lead to their death and eventual population decline.
The other issue with mechanical filtration is the trapping of organic material. This leads to breakdown of the material in the tank, leaking Ammonia, Phosphate, and other undesirables. This material could have been eaten by the aforementioned detrivores, rather than rotting in the tank, and the detrivores become a food source.
Regular (minimum weekly, if not daily) changes of the filter material reduce the impact of the latter issue to negligible. It’s possible to recover some pods and other creatures from the filter material before disposal and potentially maintaining a healthy population of organisms in the tank and hence reducing the impact of the former issue. The question has to be asked by the reefer though, does the benefit of long term use outweigh the cost?
(Note – in the case of attempting to remove the various organisms from the filtration material, many of the organisms are not viewable to the naked eye, or well camouflaged. The existence of amphipods does not necessarily indicate a healthy population of the other organisms)

Filter socks perform a similar role to filter wool but can be easier to swap in and out. Like filter wool they need to be changed regularly to avoid the breakdown of captured material.

Socks can be turned inside out and cleaned. Some methods include the following, used individually or together:

  • Garden hose
  • High pressure cleaner
  • Washing Machine
  • Bleach
  • Hydrogen Peroxide

Float valves are used for evaporation topoff, replacement of water lost from a system via evaporation. The float valve is placed in a section of the system where the water level fluctuates depending on the total volume of water in the system, typically the exit side of the sump.
Can be source from irrigation and plumbing supply, hardware and rural supply stores. Typically used for animal troughs, hydroponic top up devices or drinking water filtration.

Fluidised bed filters (FBF) are vertical columns with upward water flow, thereby keeping the contained media fluidised or suspended within the water flow. Various types of media are used to suite specific tasks. Typically, what most refer to as a fluidised bed filter is not actually being used in that manner, but rather as a fixed bed where the media does not move.

Types of media used:
Sand – various types, for biological filtration.
Granulated Ferric Oxide
Activated Carbon

Iron oxide hydroxide, also know as Granulated Ferric Oxide, is an iron based chemical medium used to remove organic phosphate compounds from aquarium water.
(Phosphate is introduced into via additions of both freshwater and saltwater, food, and is a product of bacterial decompostion of organic matter within the system. Elevated phosphate levels have been linked to the growth of unwanted algae species, cyanobacteria and a reduction in growth of corals and coralline algae.

Media is placed within a media bag, fluid bed filter, chemical media column, etc.

Media may be effective for up to a month but it is recommended to follow the manufacturers instructions for each product and use with regular testing.


Heating a tank is a fairly simple affair, just requiring a simple aquarium heater. The heater needs to be of an appropriate size to maintain the system at the correct temperature. A marine system of same size as a freshwater one will typically require a small wattage due to the other high powered pieces of equipment e.g. pumps and lighting. A good practice is to have multiple heaters to reach the total wattage required e.g. if tank requires a 300W heater then use 2 150W heaters. The reason for this is if one fails on or off, it is unlikely to cause any major problems before it is detected.

How many watts should my heater be?
As a very rough rule of thumb, a ratio of 1 Watt per Litre is helpful in choosing the size of heater. eg For a 300L tank, use a 300W heater (or 2 x 150W heaters). Of course this is only a starting point. In warmer climates, or during summer, you may not need a heater at all. In colder climates, or in winter in a poorly insulated room, this estimate may prove to be insufficient.
Also consider that lighting and water pumps can also contribute significant amounts of heat to the aquarium, and may reduce the amount of suplementary heating required.

There are a few ways you can cool a tank:

The simplest & most expensive is to buy a chiller & leave on a tank at the set temp.

Air Conditioning
The tank can be cooled by ensuring that the room temperature is lower than the temperature at which the aquarium is to be kept. Use of air conditioners can be just as energy efficient as using chillers, and has the added advantage of this is it keeps you cool as well.

Extraction Fans
Adding Fans to hoods will also go a long way to keeping tanks cool, by extracting hot air from light fittings before it can influence tank temperature. These are also linked to the next method, evaporative cooling, by assisting in the removal of humid air, therefore increasing the capacity for more evaporation to take place.

Evaporative Cooling
This bit is really worth reading!
The effectiveness of fans for evaporative cooling should not be underestimated in its usefullness. A fan blowing onto the water surface either in the main display tank or on the sump will promote evaporation, which is exremely effective in providing a cooling effect and can pull the temperature down by 3-5ºC.
Options include:
desk or pedestal fans
bathroom exhaust fans are a very cheap option for a quiet fan that moves a large amount of air.
AC or DC powered computer fans – cheap, small and flexible. Attached to a variable voltage DC adapter, a DC fan can be speed adjustable and very quiet.

Be aware however increasing evaporation will increase the required replacement rate for freshwater top off and that under humid environmental conditions (eg Tropical Northern Australia) evaporative cooling is considerably less effective and other methods of cooling will need to be employed.

If the tank is small, large blocks of frozen RO water, or frozen plastic bottles filled with water placed in the tank can help in small amounts to cool the tank down. Given that this relies on human intervention, this is to be considered as an emergency measure only. It is ineffective for larger tanks due to the large amounts of ice required. As a rule of thumb 1kg (L) of ice can provide a cooling effect of around 1ºC in 100 litres of aquarium water. Consequently reducing a 400L tank by 4ºC (say from 32ºC to 28ºC) would require around 16 kg of ice. Cooling a 60L tank by the same amount would require a much more practical 2.4 kg of ice.

Prevention is Better than Cure
Even better than implementing cooling measures is to prevent the tank from heating up to start with. Most organisms will be fine for a few days without the lights turned on. This will have a huge difference if you have large lights. Locating the tank on an internal wall, away from a West-facing walls or windows, and good room ventilation will all assist in keeping the tank cool.

What is also important is reducing the amount of heat getting into the tank from its surrounding environment. This is particularly important for systems that are situation in buildings that have poor insulation, such as tin sheds, or the sump is located externally.
Insulation Case Studies

A Hospital Tank is a self-contained, isolated tank system used to treat organisms for injuries, pests and diseases. The use of a hospital tank allows for treatments that may be harmful to other organisms to be carried out in a separate system to the display tank. Hospital and quarantine tanks are often the same system in practice.

Setting Up

A low activity area is preferable, install the equipment as a normal aquarium, bare bottom is preferred as it will help in cleaning. Fill using water from the display tank. If using a powerhead and filter combo this can be cycled in the display tank to establish its beneficial bacteria before adding to the hospital tank. Provide habitats for fish to hide in, a great help in minimising stress, lengths of PVC pipe are good for this.


To minimise stress, lights should remain off for the first day. Additionally it is a good practice to cover or shroud the tank from its surroundings, this will also help to minimise stress from external activity. Do not feed on the first day, or limit the feed and ensure it is consumed entirely. Fish are unlikely to feed at first due to the stress of relocation. When feeding is resumed ensure water quality remains high by not over-feeding.
Test water quality regularly, maintaining optimum water quality is paramount for a successful hospital stay.
Apply treatments as necessary.
Ensure that all filtration is removed during the application of treatments, most treatments that are effective on infectious diseases are also detrimental to beneficial bacteria.
Ensure the application of the treatment is carried out to its entirety, prematurely ending a hospital stay because symptoms disappear could result in the re-occurrence of the disease.

Hydrometers are used to determine the specific gravity of the water. Two types available; floating glass and plastic swing arm. They are advantageous as they are relatively cheap, easy and quick to use. However, care must be taken with the readings they provide, as some are notoriously inaccurate in the results they provide. Ensure that no bubbles or debris attached to them, which will significantly alter the reading provided.
A more preferred method of measuring the specific gravity is using a refractometer.
Most, if not all, hydrometers used in the hobby give specific gravity as the ratio of the density of the sample at 20ºC to the density of pure water at 4ºC (d20/4). Seawater with a salinity of 35‰ (35 parts per thousand) will have a specific gravity (@ d20/4) of 1.0234. The target salinity should be 35‰, so a specific gravity from one of these hydrometers of 1.023 to 1.024 is fine, depending on errors in reading or even a bit of evaporation.

Floating glass hydrometers consist of a calibrate glass tube with a specific gravity scale towards the top. They work by placing it within a calm sample of water (it will not work by placing it in the tank with pumps still moving water around) and reading the value off the scale where the water surface intersects with the scale.
They require a largish water sample, of sufficient depth to allow it to float without touching the bottom of the vessel. They are difficult to use in a tank, and it is best practice to take water sample out of tank into a container and use that. For example a jug or cut off soft drink bottle. Care must be taken, since they are made from glass and can break easily. Ensure that there are no bubbles, debris or precipitate on the surface of the glass float hydrometer, as these will change the reading.

Plastic Swing Arm are made from plastic and contain a plastic swing arm who’s height changes with density of the water and are quick and easy to use. Beware of any bubbles on the swing arm as these will increase the specific gravity reading provided, and any films or precipitate on the arm which will decrease the value. Care must be also taken with the factory calibration of the unit, since some many provide a highly erroneous reading. It is best to calibrate it against the reading from a refractometer, however filling it with pure water (which should read 1.000) is a good first step.

An Intermediate Bulk Container is a plastic tank, typically with a metal cage around it, that is used for storing water. They are used in industrial applications for moving around liquids such as oils, glues and detergents. If the material held previously by the IBC is inert or can be removed, then they are suitable for use as a water storage tank for marine aquariums.

Necessary for the operation of a DSB, live sand is sand that contains the invertebrates – critters, detrivores, etc. – that turn over sand and consume waste products. It is the invertebrates that make it live sand, not the sand itself (which is just an inert, inorganic mineral).

What is live sand?

Live sand is abundant with bacteria and micro organisms that consume organic matter and waste and in turn provide a natural food source for tank inhabiitants.
Typically, live sand that is purchased is coral sand that has been collected live from ocean water reefs ot aquacultured.
Dry sand will become live if seeded with a sample of sand from mature a reef aquarium or cultured from the addition of live rock.

Seeding non-live sand
It can be cost prohibitive to start a new marine aquarium with 100% live sand or even 50/50 live/dead sand. In most cases hobbyists that start a new tank will seed dry sand with sand obtained from a fellow reefers mature tank. Greater diversity can be gained if live sand can be sourced from several mature systems. It will take time for the sand bed to establish, but simply obtaining a cup or two of livesand and spreading it over the new sand bed will start the process.

Care needs to be taken when choosing the source if using the seeding method, the sand could be diseased or have chemical contaminants if sourced from a tank used to hospitalise or medicate livestock.

Moving a tank to a new location, be it to the next room, next suburb or next state, can be a daunting prospect, and is not without risk. However, with a bit of planning a tank move can be done quite smoothly, and without loss of life.
Here are a few tips:

Plan it out well in advance. Allow yourself about twice as much time as you think you’ll need, and start early in the day.

Have about twice as many containers / buckets / tubs on hand as you think you will need.

Bag up livestock
As far as possible bag livestock up separately, or at least with compatible tankmates. If a relatively short trip, transporting in sealed buckets and containers is fine, but for longer trips you will need to pack with oxygen, or use battery powered air pumps to keep water oxygenated.

Submerged live rock
For a short move, moving live rock submerged will help to reduce die off, and ensure a negligible ‘cycle’ once the tank is reassembled. For a longer move, the risk of exhausting oxygen becomes higher, and you may need to consider transporting the rock covered in wet butchers paper, and with a little water in the bottom of the container – just the same as how the collectors ship rock across the country.

Clean Seawater
Have about twice as much clean salt water as you think you will need, at both the packing and unpacking ends. You will go through much more than you think you might need, and it allows you to ship livestock in clean water as well (rather than the putrid crud you scoop out of the lower half of the tank.)
Any benefits of transferring beneficial organisms with the water are likely to be outweighed by the muck and detritus that will stirred up once you start disturbing the substrate. Of course care should be taken to match water parameters: salinity, temperature, alkalinity etc. Before introducing livestock, and if using artificial salt water, it must be adequately prepared and mixed, preferably a day or more before the move.

Have about twice as many towels as you think you will need . You will have the odd spill, and you can never have enough towels – trust me!

Have about twice as many helpers on hand as you think you will need, but make sure they are people who know how to follow instructions! It really helps having people around when it comes to lifting and lugging. But you’ll want to be doing all the critical handling of livestock yourself.

Glass Lifters
Vacuum glass lifting handles can be an invaluable resource for moving tanks, particularly with large tanks. Apart from being heavy, tanks are notoriously awkward to handle. Having lots of people on hand helps with the weight, and the handles help to cope with the awkward angles and fine adjustments of position.

Overflows are a method of taking water out of a tank and to a sump. Two advantages of a weir are the redistribution of water with the highest oxygen saturation and the filtration of water with the highest possible dissolved organic nutrient concentration. Overflows draw aquarium surface water and since the surface is one of the main gas exchange locations water with the highest oxygen content is circulated through the sump and redistributed throughout the aquarium. Due to the same principle that protein skimmers take advantage of, the air/water interface at the surface of an aquarium attracts the highest concentration of dissolved organics which is a highly desirable feature since these are the principle nutrients we attempt to remove from the aquarium whilst the water passes through the sump.
It is important to note that it is not possible to set up a system of two pumps, where water is pumped from one tank to another using a one pump, then from the second back to the first tank using another pump. It is impossible to balance the flow rates of the pumps so that they exactly match. So in all cases will at some point in time end up with water on the floor.

Located either within the tank or attached to the side of the tank. The most common and preferred method of getting water from the tank. Weirs and Overflow boxes can be fabricated in many styles, shapes and forms and can be disguised if made with tinted glass or overlayed with black acrylic panels.

Commonly an weir/overflow box is vertical, can be situated centrally on the back glass panel or side glass panel in the rear corner or both rear corners (in the case of a dual overflow design on larger aquariums) or diagonally across the rear corner(s)with a comb, eggcrate or Gutter Guard to prevent fish going over the side and ending up in the sump. On some Peninsular orientated aquariums (situated end on to the wall) the entire side/end of the aquarium is utilised as the overflow box with a full width comb or guard thereby concealing the overflow box as the end of the aquarium.

Becoming more increasingly popular is the horizontal weir/overflow system which can be full width across the back of the aquarium (Calfo or Coast to Coast Overflow)or partially across the back of the aquarium and with a total depth of around 150mm (6″), benefits of this style of weir is greater transfer of surface water removal and being less unsightly than a vertical weir/overflow fabrication. Additionally, combs or mesh guards can be elimated because of the shallow depth and protection of fish going down to the sump using correctly positioned pipes with strainers or fabricated elbows.(see the resources link below to Silent & Fail-Safe Aquarium Overflow System).

An alternative style weir/overflow is to silicone an external box to the aquarium and either cut out a section of glass in the rear or side panel to act as the overflow or drill several holes to allow surface water to flow into the external box. Note, there have been cases where the rear panel has cracked using this method.

Siphon Box
These are an overflow that hangs on the side of the tank, which does not have to be drilled. The siphon box is essentially two boxes, one inside the tank and one outside that are connected by a siphon. Care must be taken to ensure bubbles do not get trapped in the U tube that connects both sides, otherwise the siphon will break. These can have problems associated with the siphon not restarting after a power failure. Some designs include a suction line on the top of the siphon that can be connected to a small pump to ensure the siphon is always maintained.

Photosynthetic available radiation (PAR) and is light that is available for photosynthesis. Practically, it is defined as light between 400 and 700 nanometres (visible light) and so any light that falls between these wavelengths is PAR.

PAR is an important consideration for marine aquaria that include photosynthetic organisms such as algae and organisms with photosynthetic algae such as corals, anemones and clams. Photosynthesis is a source of energy for these organisms and they need to receive enough PAR for long enough each day to meet their energy needs.

PAR is actually the amount of light (400-700 nm) reaching the organism and is influenced by the amount of light produced by the light sources, the distance from the lamp and anything between the lamp and the organism (e.g. lids, water). Any light sources which produce light between 400 and 700 nm will contribute to PAR even if they produce a narrow band of wavelengths, such as with actinic lights.

PAR is reported in quantum units and is the count of the number of photons reaching a defined area over time. At the sea surface in full Sun at around midday in the tropics, PAR will be between 2,000 and 2,500 μE m-2 s-1 which means two thousand to 25 hundred micro Eintseins per square metre per second. An Einstein is a mole of photons and a mole is 6.0221415 ×1023(Avagadro’s Number). So 2,000 μE m-2 s-1 means that around 120,442,830,000,000,000 photons will reach an area 1 metre by 1 metre every second.

Some people confuse PAR with light output and think that the PAR of a lamp can be defined. This is a misunderstanding of PAR. One way to show this it to use a torch in a dark room. With a standard torch, the light output will be essentially the same (until the batteries go low). If you shine the torch on a wall on the other side of the room, the light will be spread over a large area. If you then walk towards the wall still shining the light on the wall, the area the light covers will get smaller as the torch gets closer to the wall, and the brightness increases. Same light output, different PAR depending on the distance.

Powerheads provide important water circulation and oxygenation in the aquarium, far more efficiently than the bubbles from air stones do.

They help to keep detritus and other tank matter from settling on the bottom of the tank. Powerhead circulation permits the majority of these particulates to be circulated or suspended, allowing them to be filtered out by a mechanical filter.

They aid in the health of the tank inhabitants. Water moving over the animals helps to carry oxygen to them, brings food to stationary animals, and stimulates animal activity. Learn about the animals you are choosing for your aquarium. Many corals and anemones do not do well in high current areas, while others thrive on good strong current. Position them appropriately in your tank.

The water movement and currents provided by powerheads are a source of exercise for fish.

Be sure the powerhead you choose is saltwater safe!

Pick a powerhead that can be taken apart and put back together easily. Over time buildup can enter the impeller area and needs to be removed. Look for ease of cleaning to prevent restricted water flow, which in turn can lead to the unit burning out prematurely from overheating.

Choose a powerhead that you can order and replace the parts on. 

Be sure the powerhead has a strainer or screen of some type that covers the water intake hole to prevent unwary tank inhabitants from getting sucked into it. 

This can be further complicated by tank matter clinging to the strainer. This clogs the unit creating even more restricted water flow, and overheats it prematurely decreasing the life of the unit. Overheating units can also add an extra unwanted heat source in the aquarium.

Some powerheads have switches for adjusting the water rate up, down, or in a reverse flow. If you want less current in a particular area of your aquarium, you can opt to turn down the water flow automatically.

Protein skimmers have the reputation of being an important part of the filtration for a marine aquarium. A system can run without one, but alternative methods of performing the same function has to be employed. They are a very simple piece of equipment that brings aquarium water into contact with tiny air bubbles, which dissolved organic molecules will attach to, the bubbles then rise to the top of the chamber, form a foam, which is then collected and removed from the system. The material collected is called the skimate.

Types of Skimmers

There is a multitude of different types of protein skimmers available, each one using a different method of introducing the air into the water and creating smaller bubbles. There is no best type, as each of them have their own advantages and disadvantages, making them more appropriate for a particular situation.

How are the bubbles generated?
Methods include:

Airpump and limewood airstone.
Limewood provides a much finer bubble size than ceramic airstones typically used in aquaria

Water pump forced through a venturi valve.
Where water passing a constriction in pipe diameter produces a reduction in pressure allowing air to be sucked into the water the water stream where it is then broken by turbulence into small bubbles

Aspirated water pump
Where an air inlet is inserted to the intake side of a water pump. Air is drawn into the water stream by means of the venturi principle, and broken into small bubbles by the pump impeller. Some pumps working on this principle utilise a needle wheel impeller, said to assist in bubble size reduction.

Foam Jet
Also operating on the principal of a venturi valve, foam jets are nozzles designed for producing a foaming stream of water for use in pond water features or fountains

It is highly recommended that this unit is the first piece of water testing equipment that should be purchased by the new hobbyist.

A refractometer is arguably the best and easiest method of determining the salinity – the most fundamental of water parameters in the marine aquarium. It measures the degree to which light bends (or refracts) as it passes through a sample of water. The degree of light refraction is proportional to the level of dissolved solids in the water sample, which in the case of salt water means the salinity of the sample.

Refractometers typically available to the hobbyist are small hand-held units. Several drops of water are placed on a glass panel, and the unit is held up to a light source and the hobbyist reads the salinity level on a scale through an optical eyepiece.
A major benefit of a refractometer is that it requires only a few drops of water to obtain an accurate salinity reading, which makes it invaluable in effectively acclimating new livestock from transportation bags to the aquarium. Alternative salinity measurement devices such as floating glass hydrometers or plastic swing-arm hydrometers require a significantly larger water sample. Most refractometers are self-correcting for temperature effects and are quick and easy to use. It is recommended to allow some time for the water sample and refractometer to equalize to the same temperature before taking a reading.


A refractometer should be calibrated prior to first use using pure water, distilled or reverse osmosis (RO) water. Distilled, deionised (DI) or good quality RO/DI water will have a specific gravity of 0.000 or salinity of 0 ppt. Tap water from the vast majority of locations will also show a specific gravity 1.000, there is insufficient dissolved material to increase it to a detectable level.
For calibration at 35 ppt salinity / 1.0264 specific gravity (that of NSW) a reference solution can be made from water and table salt (sodium chloride, NaCl) using one of the following measures (scales used should be accurate to at least half a gram):
14.2g salt and 375.0g of water
14.6g salt and 385.4g of water
20.0g salt and 528.0g of water
36.5g salt and 963.5g of water

A refugium is, quite simply, a place where organisms on the bottom of the food chain can grow and thrive without predation.
Common implementation of refugiums are in a sump. However places like the weir, in tank “cages” and hang on refugium types are all options for this.

The main objective is to have critters like ‘pods, polychaetes, and other microfauna reproducing. Most of these critters are not only detrivores (wonderful cleanup crew) but their offspring and even themselves find their way back into the tank and become food for fish and coral. Other beneficial organisms include algae, but this is mainly directed at the Macro algae refugium
If implementing a refugium, it is favourable that there is no pumps between it and the main tank. For most systems this in unavoidable, especially a sump implementation. The next best thing would be to use air lift pumps. However even using normal pumps, a decent percentage manage to survive the shear forces in normal impeller return pumps and make it to the main tank

Macro Algae Refugium
When many people talk about implementing a refugium, they are usually referring to a Macro algae refugium. The difference between a normal refugium and a macro algae refugium is that a light source is introduced, along with some fast growing macro algae such as Chaetomorpha.
The growing of macro algae in a refugium provides the ability to export nutrients, by the removal of excess algae growth. The growth of algae absorbs the nutrients and by harvesting the algae the system is rid of the nutrients. Many also use this excess algae to feed herbivorous fish like tangs and rabbitfish.

Should my refugium lighting be opposite to my main tanks lights?

It can be, the reason for this is to help off-set the changes in pH that occur in the main tank during the day/night cycle….
When the Coral and Algae in the main tank are exposed to light, oxygen is produced as a byproduct of the photosynthesis process and carbon dioxide is consumed, this removal of carbon dioxide from the water causes the pH to rise. So when coral and algae are not exposed to light the production of oxygen is reduced and the production of carbon dioxide is increased, which leads to a decrease of pH during the periods of darkness. These fluctuations can be eliminated to a great extent by lighting a refugium in an opposite cycle to the main tanks, minimising the pH fluctuations and maintaining the amount of dissolved oxygen constant in the water.

Pump used to circulate water from the sump to the display system. Generally speaking the return pump should circulate approximately 3 to 5 times the tank volume through the sump but its variable to suit individual systems.

At its simplest, a sump is a secondary tank or container that is plumbed to receive water from the main aquarium before it is returned to the main aquarium. Whilst often being made of glass, and with the inclusion of various baffles and compartments, any container that holds water can be used as a sump, such as a plastic tub or bucket.


Most commonly sumps are designed in three sections seperated by baffles (to minimize micro bubble transfer back to the display tank), the first section being where water is overflowed from the display tank and ideally where an internal protein skimmer is situated, the second section utilised as a refugium, DSB (Deep Sand Bed) and facility to grow Macro Algae (that takes up nutrients and can then be exported/removed by trimming/pruning back)this section needs to be under light(s) to promote macro algae growth, the third and final section is for the return pump – it is also the section that will indicate the optimum water level of the system when running. This level needs to be set at a height that will allow water returning to the sump when all power is switched off or in the event of a power outage but not so low as to run the return pump dry. It is beneficial to mark this level on the side of the sump with a permanent marker, tape or Dymo label to indicate how much water is lost through evaporation.

Water evaporation could be in the vicinity of 5 to 10 litres per day on a 4x2x2 aquarium with two 250 watt Metal Halide Lamps. Note: water that has evaporated from a saltwater aquarium is topped up with fresh water (not saltwater) as only the water has evaporated not the salt content.
Hobbyists numbers today are continually growing and so to are the size of their aquariums, in the past a 6x2x2.5 aquarium would have been considered large, it is now common to see home aquariums 7′, 8′ and 10′ Wide by 3′ and 4′ Deep and up to 3′ High. Consequently, the size and style of sumps has also advanced and we hear terms like “RaceTrack design”, effectively this means that the sump is partitioned lengthways as well and water flows down one side and back the other and incorporates more sections for various other components/options, perhaps a dedicated area for filtration media, a DSB (in addition to the refugium), a compartment to house Zeovit, calcium reactors or fluid bed filters, a coral frag facility or even an isolated compartment to be used as a fresh water top off reservoir.


The major benefits of having a sump are:

  • It increases system water volume, for improved stability of water parameters;
  • It allows for the maintenance of constant water level in the display tank, with water level variations due to evaporative losses occurring in the sump.
  • It provides a place to put equipment that would be preferable to not have in the tank, such as:
    • Heater
    • skimmer
    • dosing/top-up equipment (float valves/switches,
    • calcium carbonate reactors, etc.)
    • activated carbon (if so inclined)

Avoiding Wet Floor

It is worth noting that when the return pump is turned off, it will form a siphon and water will backflow through the return line, through the pump, and back into the sump. This will continue until water drops to such a level that air is drawn into the return line and the siphon is broken.
Care must be taken to ensure that the capacity of the sump is such that it will cope with the volume of water that backflows until the siphon is broken. For this reason, sump return pipes are normally placed near the top of the display tank to minimize the amount of backflow before the siphon is broken, and so that a backflow siphon does not totally empty the display tank in the event of a power outage. Alternatively, a series of small siphon break holes may be drilled into the side walls of the return pipe just below the water surface level in the display tank to enable air to be drawn into the pipe as soon as the water level drops by a small amount.

Used to make joints between glass panels, to allow construction of a glass tank, or can be used for modifying water exposed items within the tank itself. Silicone is available in many forms, not all of which are suitable to aquarium use or for plumbing within tanks. Check the label carefully as to suitability of each particular silicone, most require several days curing before they are safe for use in a water exposed situation.

Silicone should be used in a well ventilated area which not only promotes curing but removes any fumes from the curing process. Typically aquarium or glass type silicone uses a form of acetic acid to maintain the maleable state, and thus can produce significant fumes which may be harmful. The release of such fumes is also one of the main reasons adequate time should be allowed before use in a tank. Generally this process takes from 5-7 days and this ensures that the bonded surfaces are well attached and not as susceptible to water leaks. 

It is recommended that plumbing and tanks are tested for leaks after using silicone to ensure that any leaks do not exist. Before use within a tank system ensure any exposed silicone is washed thoroughly as excess curing residue may be present on the surface.

Supa glue (cyanoacrylate adhesive) can be used for mounting coral frags in the aquarium. It can form a strong secure bond in a relatively short time frame, and with the right techniques (and lots of practice) can work underwater.

It works best on stony corals and other hard surfaces. With some care it can be used on some soft corals, but is not nearly so effective due to the copious amounts of slime that they organisms generate. Other physical methods of attachment, such as rubber bands, toothpicks, wedging, rubble bowl etc. work better for soft corals, corallimorphs and zoanthids.

The most effective form of the glue is the thicker textured Supa Glue Gel, rather than the thin watery type. The thinner types can be thickened some by placing in the freezer before use.

It must be noted that working with supa glue underwater is not foolproof, and it normally takes a few goes before you can get it to work. You will need to develop your own techniques that work best for you, but here are a few tips:

  • If possible, remove one or both of the items to be glued from the tank and dry off with paper towel before applying the glue. Even if you can only do this to one surface, you will at least have a good bond to one side.
  • Use LOTS of glue. It really doesn’t stick all that well underwater or to wet surfaces, and you need to make sure there is plenty to go around.
  • After applying the glue, let it start to dry / skin over for a few minutes before trying to place it into the tank.
  • When you press it into place, hold it firmly for a few minutes (say 5 minutes). The glue doesn’t dry instantaneously. (that’s the really boring bit, and can be particularly awkward if you’re standing on one leg reaching to the back corner of the rockwork.)
  • Supa glue can be used in conjunction with epoxy putty combine the adhesive benefits of supa glue with the customisable hard physical shape of epoxy.

Test kits are a method of a determining the value for various water parameters. Generally, it is unwise to take the values generated by a hobbyist-grade test kit as the absolutely correct value for what conditions the water sample is currently under. It is far better to use them as a guide, particularly for trends over time. Chasing the “perfect numbers” is a very bad idea and will typically cause more trouble than it is worth.
Also of concern, is what parameters to test. Generally, not everything is equally important, see What Parameters to Test for more information on this.
If an unusual reading is obtained or a new test kit is purchased, then it should be validated.


There are three main methods utilised in hobbyist kits: colour matching, titration.

Colour Matching
With colour matching, a measured sample of water is placed in a vial or similar (Seachem use wells), one or more reagents are added to the sample and the resulting colour of the sample is compared to a colour chart. This method is used for most test kits for most parameters. Accuracy is dependent on the lighting under which the comparison is made and is influenced by the judgment of the person doing the test.

Titration kits are generally used for alkalinity, calcium and magnesium. A measured sample of water is added to a vial or well, one or more reagents are added to colour the sample and then a titrant is added slowly until the colour changes. The quantity of the titrant added determines the concentration. Titration tend to be far more accurate as they are not subject to human judgment of colour.

In addition to manual Test Kits where a visual comparison of colour against a colour chart Electronic Test Equipment is becoming more affordable for the average hobbyists and provides a more accurate result of the particular water parameter being tested.

Traditional aquarium heaters have a thermostat integrated in the construction of the heater unit. The thermostat detects the water temperature and activates the heating element when the temperature drops below the set point.
By having the thermostat in such close proximity to the heating element, the measured water temperature can be influenced by whether or not the heating element is running at any particular time, with the result that traditional aquarium heaters have a limited ability to control temperature closer than a range of +/- 2ºC. In many situations, this is more than adequate.
A solution that enables temperature to controlled much more tightly is to use a separate thermostat with a temperature sensor located remotely from the heating element from the heater. Using such a sytem, aquarium temperature can be controlled much more tightly (say +/- 0.5ºC), leading to superior stability.

Topoff for tanks is vital, as pure water evaporates and needs to be replaced with pure water. Maintaining a constant water level will assist greatly in maintaining a constant level of salinity. This in turn has a major impact on the stability of the aquarium system in total.

Since evaporation only removes pure water vapour, the salt and other dissolved components are left in the tank. It is therefore important to only top up evaporative losses with pure water.
Replacing evaporation with salt water will result in significant increases in salinity level, which will be detrimental to marine organisms. However, this can be used in the short term to slowly increase the systems salinity if it is too low.


There are a number of different techniques that can be used to add water to a system to replace that which has evaporated.

Simply pour fresh water into the tank to the required level. This can create issues with large salinity changes between top ups, this is not a recommended way of doing things unless you add small amounts frequently. Particular care should be taken in small aquaria, where an addition of only a few litres of fresh water can have a significant effect on tank salinity.

Simple method of restricting the output from a container so that the drip rate is consistent with the evaporation rate. It must be noted that it may prove difficult to exactly match the top-off drip rate exactly to the rate of evaporation, and care should be taken to closely monitor the system and corrections made to compensate.

Automatic Gravity Fed
By using a float valve connected by siphon feed to a freshwater drum (reservoir), water will be topped up to the tank as it evaporates, maintaining the water level where you want it and maintaining salinity at a very constant level. All you have to do is make sure the reservoir has fresh water in it, and that the water level in the reservoir is located higher than the water level in the aquarium to maintain the siphon flow.
Float valves can be sourced from irrigation and plumbing supply stores, and are often used for animal trough or hydroponic top up devices. Be sure that the float valve is all plastic in construction, and does not contain any metal parts. 

Automatic Electronic
These are similar to the gravity fed system, except they use an electronic float switch to control a low flowrate dosing pump. Peristaltic pumps are a good choice, as they are able to consistently deliver a very slow, measured flowrate, and are tolerant of running dry if the reservoir is emptied.

An ultra violet (UV) steriliser is chamber that exposes water to ultra violet radiation to kill free floating micro-organisms. A UV steriliser will not only kill bad things but will also kill plankton and beneficial organisms that also go through it. They are used primarily to kill bacteria, fungi, algae etc. and are extremely efficient, unless set up incorrectly.

An UV steriliser works by emitting ultra violet radiation that mutates cells as they travel through the UV light and is lethal to living tissue Tank water is circulated through the unit where it is exposed to the UV radiation. If the amount of UV radiation and contact time are appropriate, everything within the water will be killed. However, if the water flowrate through the chamber is too high, there is insufficient time for the cells to receive a lethal dose of light. The water flowrate through the UV steriliser must be matched correctly with the UV tube to ensure appropriate irradition rates and contact times. This is first area where UV sterilisation is utilised incorrectly and fails to work as it should. If the unit is too small and/or the flow rate through it is too high, many organisms can pass through the unit unharmed.
Similarly, if there is no or insufficient mechanical filtration before the water passes over the UV tube, large particles can create shadows which decrease the efficiency of the steriliser.
The use of UV will not effect any other life within a marine system. This is due to the fact that is can only mutate living organisms that actually pass through the contact chamber, it does not effect the chemistry of the water (as ozone does) so the effects cannot be transferred back into the display tank.

Do I need a UV Steriliser? For the average, general reef aquarium hobbyist, no. It is far better to spend the funds on some other more key equipment for the system. They can be helpful with a large fish only type of tank or for use on a hospital tank to reduce parasite numbers. One issue with using on a reef tank is that it does kill anything that passes through the unit, including the “beneficial” plankton. They are not useless, need to set up and applied correctly, but for the average hobbyists, a UV steriliser is not required.

Will a UV steriliser kill ich? UV sterilisers are not designed to kill complex organisms such as cryptocaryon (marine ich). Cryptocaryon and Amyloodinium don’t spend enough time in the water column for the UV steriliser to be able to eliminate them. However, UV steriliser might reduce the number of parasites so they don’t cause a problem but once its is turned off, parasites can reproduce again.

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