surprisingly not overly hard to care for -- they just have a specific dietary requirement you have to fill. They're slow, deliberate feeders, so if you have other fish in the tank, give them their meal first. You pretty much have to hand feed them, and by hand I mean turkey baster, or set up a feeding station. The key to setting up a good community tank with horses is research the most peaceful fish and (preferably, though not necessary) add the tank mates AFTER the ponies are in.
sea horses like cooler temperatures, so assume you won't be running your heater for this tank. I live in florida, but the ambient house temo is 75 and the tank is always around 73....no chiller needed. But I put the tank in a darker room and the lighting is low-light standard fluorescent, so that makes a difference.
By the way, awesome tank there, Pete!