What is the best powerhead for a reef tank?

Water movement is one of the most essential parts of any reef tank. Corals use water movement to bring them their food and wash away their waste, and although some corals can survive without light, none can survive without flow. 

Traditionally, powerheads were used to move water around the tank. A powerhead is an aquarium water pump, aimed originally at fitting to the top of an undergravel filter and increasing the water flow through it by pumping more water than a standard air-powered uplift. 

Issues

Powerheads were essential to early reef tanks and many tanks had multiple powerheads, all pointing and pumping in different directions in order to move the water like something resembling a natural reef. There were issues though. Most powerheads delivered around 1000lph – a lot for an undergravel filter bed but not much in the greater scheme of things when trying to replicate a natural reef. So use lots of powerheads, like six for example to pump 6000lph, and you not only need six powerpoints, you also have six unsightly pumps in the main display tank and the heat generated by six pumps would cause your tank to overheat.

The other issue with powerheads is that they have quite a narrow outlet, causing a thin jet of high-velocity water, and the inlet is also narrow causing high-velocity suction, and frequently causing fish, inverts and anemones to get stuck to them, often proving fatal. Enter wave pumps…

Wavepumps took the same magnet driven pump bodies but altered the impeller to look and work more like propellor, and cut the narrow spout outlets off, enabling much more water volume to be moved at any one time, with much broader, lower velocity flow that corals prefer. Now just one wave pump can replace six, ten or even 15 powerheads, producing less heat but using just one socket and moving just as much water. As we learned more about captive coral husbandry total tank water turnover increased from 10 times per hour to 20, 50 or even 100 times per hour in some tanks. This wouldn’t be possible with standard powerheads. 

Control

The other thing that some wave pumps enable is greater control. A standard powerhead is powered by AC with just on or off being the only possible control method or using a plastic flow restrictor, yet still using full power at the wall. Most wave pumps are now DC, meaning that their flow rate can be turned up or down by controlling how much power goes to the driver. Turn a DC wave pumps flow down and it will use less electricity. Turn it on and off in quick succession and it can pulse, producing waves and more natural flow cycles. Use a wave pump with app control and virtually anything is possible like when it comes on or off, ramping up and down, short pulses, long pulses and even storm effects, whipping up strong currents in the aquarium to life detritus up off the bottom.

Modern, controllable wave pumps (also known as wave makers,) offer water movement in abundance while enabling the owner to harness that power and flow pattern how they see fit to suit the needs of their corals.

Which wave pump is right for me?

The best wave pumps come with magnet fittings to clamp them to the side of the tank, versus rubber suckers which may lose their suction over time. Aim for at least twenty times total tank volume to get started, so that means a wave pump producing 1000lph for a 50 litre nano reef, 5000lph for a 250 litre mid-sized reef and 10000lph for a 500 litre reef tank. For mid and large-sized reef tank you could split that flow recommendation into two pumps, with one at each end, as many high-end wave pumps can work together in a controllable master and slave mode, and in sync or anti sync, producing desirable push and pull water flow across the tank. So use 2 x 2500lph for 250litres, and 2 x 5000lph for 500 litre tanks etc. 

As corals grow, the more water flow is deflected and dissipated, so extra pumps can be added over time. Or buy an oversized pump, first of all, running it on say 50% output, then turn it up as corals grow and spread to keep water movement strong throughout the tank.  

So the best powerhead for a reef tank is a DC controllable, magnet mounting wave pump that turns over your tank’s total volume at least 20 times per hour.

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Jeremy Gay is an author and freelance aquatic specialist. A former editor of Practical Fishkeeping magazine, he offers a wealth of experience on all things aquarium and pond.


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