Circulatiom Pump for my 20 gallon Nano Reef

[Data]

Hi! I cannot seem to find a circulation pump any smaller than 500 gph and am afraid it is too much, particularly considering that I already have a hang on back filter rated for 70 gallon aquariums. So is 500 gph too much for a 20 gallon nano?

 

[Ron Reefman]

It's probably at the upper edge. But you can install a ball valve (or better, a gate valve) to slow down the flow.