Well, that's quite fancy.
If you already have a sump, and you don't plan to make you refugium part of the display, why not just use a bucket? Or some kind of large plastic container? It can be cheaply bought at any hardware store, clean it out with some vineagar, cut a hole and silicon in a bulkhead. Then you can have a pump feed water to it from your sump and it could gravity drain back into it. THat's how I set up my refugium in my old tank, and how I will be setting it up in the new tank as well. This makes the refugium totally independent (for easy removal if necessary) and gives you a greater control over the flow through it than if it is part of your sump system.