Jeremy provides an overview of some of the other key bits of equipment that’ll you need to power your reef aquarium.
Over the last few articles in this beginner reefkeeping series, we’ve covered some of the biggest decisions when setting up a marine aquarium:
But the shopping list doesn’t stop there.
Once the main equipment is in place, there are several other pieces of kit that play an important role in keeping a reef aquarium stable, healthy and running smoothly. Some are essential from day one, while others become increasingly valuable as your aquarium matures and your collection grows.
Here are the key pieces of equipment that deserve a place on your reef-keeping checklist.
Heaters: keeping things stable
As tropical marine fish and corals are accustomed to warm water, a reef aquarium should generally be maintained at around 25°C (77°F). That means a reliable heater and thermostat are essential.
This isn’t an area where it pays to cut corners. There’s little sense in relying on a £20 heater to protect £2,000 worth of livestock. Invest in the best-quality heater you can reasonably afford and choose one that can maintain a very stable temperature.
Natural coral reefs are remarkably stable environments, so corals aren’t especially well adapted to dealing with changing temperature. A good heater is therefore less about simply making the water warm and more about keeping the temperature consistently within the correct range.
Some corals are more tolerant to changes in water chemistry, and these are generally the ones more often recommended as beginner corals.
Return pumps: the heart of your filtration system
A return pump is an essential part of most reef aquariums. Unlike wavemakers, which circulate water around the display aquarium, the return pump moves filtered water from the sump or filter compartment back into the main tank.
Water from the display passes through the slots in the weir or back filter section, where it is filtered before being pumped back into the aquarium. The return pump therefore provides the vital connection between your display and your filtration system.
As a general guide, aim for a return pump capable of turning over the system volume at least 10 times per hour. For example:
- 250-litre (55-gallon) aquarium: around 2,500 lph (550 gph)
- 600-litre (132-gallon) aquarium: around 6,000 lph (1,320 gph)
However, don’t simply buy a pump based on its headline flow rate.
Manufacturers usually quote maximum flow with the pump operating at 100% power and at zero head height. In a real aquarium, the pump may need to push water several feet upwards, and this reduces its actual flow – a phenomenon known as head loss. Narrow pipework, bends and manifolds can reduce flow further.
For this reason, it’s generally better to choose a slightly more powerful return pump and run it at a reduced setting than to buy an undersized pump that struggles to provide sufficient turnover.
Reef tanks with poor circulation may suffer from particles in the water, dead spots and settlement in the sump. Since most of your filtration takes place in the sump or back filter chamber (for All In One tanks), you need to ensure that the dirty tank water is getting to the filtration several times an hour.
Where possible, look for a DC controllable return pump, operated via a wired controller or smartphone app. Being able to adjust the flow gives you much greater control over your system.
Auto top-offs: controlling evaporation
An auto top-off (ATO) system automatically replaces water lost through evaporation – and it can make a surprisingly big difference to the stability of a reef aquarium.
All tropical marine aquariums experience evaporation, particularly open-top systems with sumps. It isn’t unusual for a reef tank to lose 25 litres (5.5 gallons) of water a week or more, depending on its size, temperature, airflow and room conditions.
The important point is that when saltwater evaporates, the water leaves the aquarium but the salt remains behind. As a result, the aquarium’s salinity gradually rises.
This matters because the natural marine environment is exceptionally stable, and reef organisms are not well adapted to frequent changes in salinity, just like they aren't well adapted to changes in temperature.
Evaporation can also create another problem. As the water level in the sump falls, the return pump chamber can become low enough for the pump to start drawing in air. This can produce the familiar “blowing bubbles” effect that some new reefkeepers notice shortly after setting up a tank.
Left unchecked, the situation can quickly escalate: the pump may eventually run dry, circulation can stop, salinity will continue to rise and further evaporation makes the problem worse.
Fortunately, the solution is straightforward.
Top up evaporated water with reverse osmosis (RO) water, not saltwater. Adding fresh RO water replaces the water that has evaporated without increasing the aquarium’s salinity.
Better still, let an ATO do the work for you. Using sensors, float switches or float valves, an ATO monitors the water level and automatically adds RO water from a reservoir when required. Some sumps even come with a small RO reservoir when you buy them, others you may need to utilise a separate container like the one by Red Sea below.
For many reef aquariums, an ATO is one of the most useful pieces of equipment you can buy – and one that shouldn’t be overlooked.
Reactors: getting more from your filter media
Reactors are cylindrical chambers designed to hold mechanical, biological or chemical filter media. They are normally installed in the sump and powered by a small pump, which moves water through the media before returning it to the sump.
One of their most common uses is for phosphate-removing media. While phosphate remover can simply be placed in a media bag in the sump, a reactor allows water to pass through the media continuously and more evenly, making much more effective use of it.
Reactors can also be used with a variety of other media, including:
- Activated carbon
- Biopellets
- Biological media
- Macroalgae
They provide a neat and controlled way of housing filter media while maximising its contact with aquarium water.
They aren’t necessarily essential on every reef tank from day one, but as your system becomes more sophisticated, a reactor can be a very useful addition.
Chillers: keeping summer temperatures under control
Heating gets plenty of attention in reef keeping, but cooling is just as important.
Corals can actually be less tolerant of excessively high temperatures than moderately low temperatures, with temperatures above around 27°C (82°F) potentially becoming a serious concern.
That makes summer heatwaves a particular risk. There are various short-term ways of reducing the temperature of an aquarium, such as using a fan to increase evaporation or placing frozen packs in a top-up reservoir. However, these approaches require monitoring and aren’t always practical.
A better solution can be a dedicated cooling fan (pictured above) controlled by a thermostat, which switches on automatically when the aquarium temperature rises above your chosen level.
For maximum control, you can invest in a refrigerant aquarium chiller. These are larger pieces of equipment that usually sit outside the aquarium cabinet and use refrigeration technology to bring the water back down to the desired temperature.
You may not know whether you actually need a chiller until your aquarium has experienced a full year of seasonal changes – including a few hot spells. If temperatures remain comfortably under control, you may never need one.
But if your aquarium is becoming a valuable collection of corals, a chiller can be a worthwhile investment in protecting that livestock from extreme summer temperatures.
Don’t forget the power supply
By now, it might seem like there’s an endless list of equipment required to run a reef aquarium.
The good news is that not everything needs to be installed immediately. Some equipment becomes useful as your aquarium develops, while other items are essential from the start.
What they all have in common is that they help create the stable environment that fish and corals need – keeping the water clean, circulating, illuminated and at the correct temperature.
Think of your aquarium as a home from home for its inhabitants. The closer you can get to providing the stable conditions of a natural reef, the better your chances of long-term success.
Finally, don’t overlook something as simple as the power supply. Use a good-quality multi-socket extension or power distribution unit, ideally with six to twelve sockets and individual switches where possible.
Once everything is connected, take the time to organise the cables neatly and safely. A dedicated controller or cable-management board can make a huge difference, keeping the installation tidy and making it much easier to identify, maintain or replace individual pieces of equipment.
A well-planned reef aquarium isn’t just about choosing the biggest or most expensive equipment. It’s about putting together a system in which every component has a job – and where the whole system works together to provide a stable environment for your fish and corals.