More information regarding your system would be needed (size, equipment, etc).
I have seahorses in a reef tank but I set the tank up keeping seahorses in mind. I guess one thing to consider is how much Mysis would you have to put in the tank to make sure the SHs are getting their share after your other fish are done. This could also cause potential water problems escpecially since feeding SHs 3x a day is the best way to raise healthy SHs. Of course that is my opinion based on experience.
You mentioned you know all about seahorses so I imagine that you know what species would be best suited for the warmer temps of a reef tank. In case you haven't run across this site (
www.seahorse.org), I suggest you do some reading there. Heat coulde be a problem to keep in mind because your SHs will be eating fine and then all of the sudden die off as most species are not accostomed to constant temps of 75 degrees or more.