Mike, Did you have a sump when you had seahorses? I ask this as the one we are setting up has no sump. and seahorses don't like strong currents. we are looking at splitting the filter suction into 4 smaller pipes and placing them at the rear of the LR. So as to pull the water through the gaps between the LR. 1 Small powerhead aimed at the LR face, we hope this will give enough flow to eliminate pockets of stale water.Mike said:I've kept them and IMO they really need their own tank. Most saltwater tanks need brisk circulation and the seahorse likes very slow flowing water currents. They can be difficult to feed and need some sort of place to hold onto in the tank with their tails. Keeping them with other fish will make it very difficult to feed since they are very slow and PICKY eaters.