I am trying to find info re a 180g seahorse tank. The book that I want is backordered, and the seahorse sites I have found don't help much. I've talked to a local "expert", and was told that 180 is too big. (not my LFS)
 Needless to say, "SAY WHAT?" Isn't the ocean bigger than 180g???
The Vancouver Aquarium has a seahorse tank  that is more or less 150g looks like it has a DSB and seagrass, maybe 40"deep total. Is there a more ideal setting for seahorses? 
The more we can set up our  systems for captive breeding, the better, I say!
Mitch