A key factor to keeping a thriving SPS dominated reef tank is having a lot of water movement and there are a number of reasons why strong circulation is important for SPS. Number one is to keep detritus from collecting at the bottom, which helps to keep nitrates and phosphates from building up in the tank. Be strategic with the positioning of your pumps and create an aquascape that will be free of detritus traps. In my post Aquascaping – Less is More, I discussed how detritus build-up was prevented in the back of my 225 gallon tank with some Tunze pumps located between the live rock and back panel of glass.

 

Having strong flow also helps to deliver food and nutrients to corals so it is important to avoid dead spots and have consistently strong flow throughout the reef. I am also a believer in having strong surface agitation since it helps to increase oxygen levels and replicates the light refraction that occurs in our natural reefs. Rimless reefs are very popular but I prefer euro-bracing since it prevents water spillage in tanks with strong surface flow.


Good water circulation can also help to prevent problematic algae from taking hold in a tank. Again, avoid dead spots and strive to have strong flow throughout the tank. Besides strong flow, random flow is also beneficial and can be achieved by using a re-circulating pump such as an Ecotech Marine MP40.

 

How Much Flow?

So what is the right amount of flow to have in an SPS dominated tank? Opinions vary on this but I would recommend a flow rate in the range of 40-60 gallons per hour (GPH). This is the number of times per hour that the water volume in the display tank is moved. As an example, a 200 gallon tank with a GPH of 10,000 would have a flow rate of 50X.

 

One thing to be aware of with a mature reef tank is to not let it become overgrown with corals. Sure, everyone aspires to have good coral growth but if you allow SPS colonies to get too big they will likely start to die off near the base where they will receive less light and flow. Large colonies can also reduce flow in a tank and potentially inhibit the delivery of nutrients to other corals, which may lead to Slow Tissue Necrosis (STN) or even Rapid Tissue Necrosis (RTN).

 

 

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There are many variables involved in having a successful SPS tank and strong circulation is certainly one of them. So remember to “go with the flow”. Your SPS will be happy you did.

 

If you are looking for additional insights and information, you can explore my many other reef tank and SPS related articles as well as my book, A ReefBum’s Guide To Keeping an SPS Reef Tank: A Blueprint For Success. Additionally, you can see all of my reef tank videos online now as well as my Live HD Webcam. And if you are interested in purchasing pumps and skimmers from Royal Exclusiv, algae reactors from Pax Bellum or a wide range of products from GHL, including dosing pumps, Profilux 4 controllers, the KH Director and ION Director, then please visit my store.

 

Happy reef keeping!