Well see - you've already got it figured out :lol: :lol:
I am not one to jump all over you with regard to the pipefish thing, after all I too want to try it. If you bought your seahorses from a LFS they were probably already mixed with pipefish anyway. It has its risks but I imagine with proper QT and management, the risks can be minimized. You have had all of yours for a while now haven't you?
I would definitely 100% QT any new additions that's where I think most of the risk lies. I just ordered some pipefish from Liveaquaria, they will not be mixed with anything for quite some time.
I'm assembling quite an assortment of macroalgae so if you need some for that new tank, give me a holler.