While most people don't usually have mechanical filtration on saltwater tanks, I really recommend it for any tank. I have a canister filter on my 30 gallon- a lot of output but the macro, rocks, and depth of the tank kind of absorb its effects. Most CB horses eat mainly frozen foods, and it degrades water quality a lot faster than flake food does. I have 3 filter pads, a bio pad, and bio filter rings in my rena xp1.
Good luck with your attempts! I just got my latest seahorse and I love it :