Doesn't matter now that they have sold, but they absolutely do not belong in a reef tank.
Talk to any seahorse keeper, breeder specifically, who has kept them with any kind of moderate success. They can't be kept successful, without taking huge risks.
Here's a couple:
Pathogens, seahorses are susceptible to many pathogens, and fish carry a lot of stuff they simply don't have immunity to, especially bacterias (vibrio etc)
Second, they are slow feeders, and can't compete with more boisterous species.
Lastly, they eat alot, very heavy amount, and will pollute your tank.trying to keep any acros or sps for that matter would be tough.
Lastly, any kind of good water flow requires some fas spinning props. Even to get moderate flow, you need a good power, which will either a. Suck in and shred the seahorse to pieces, or, make it want to Hitch all the time, as opposed to swimming around getting blown into rocks.
It's not so much you cant do it, it's just cruel. They need species who let them eat (none), species without diseases they already have a natural immune system for (none) and slow moving water, without dangerous spinning blades (don't know of any reef a power head)
Lastly, an anenome can grab a fast moving fish, why would you chance that with a seahorse?
