closing the hood is really going to limit you. you can cut a hole in the top/back and mount a small fan, leave the tops open, or get a chiller are your three options.
I've got a montipora undata frag that looks like this (less purple on the edges, more of a light blue) http://www.reeffarmers.com/limitedmontiporaundatatrue.htm
They won't grow on the sps themselves, but they will infest the plugs. They also don't sting , so that's a bonus. They do however "spawn" or break off and move around at will.
I'm the resident bcp expert/victim. Once they're in there, you're gonna have a tough time getting them out. I have a miracle cure you can try, but it will toast crabs and softies.