Have you ever seen a Xenia excrete anything? I don't think so, because of that, they are eating sediment and using it to grow, much like algae on a scrubber. This can also work with leathers and gsp. I think the best would be gsp and Xenia just because of their body shape. I will try it and report Back whenever I get all the supplies, but I warn you, that might be a little while.
I heard about this in a garf video. They say there is less die off of xenia when multiple species are present.
My idea would be to have several units of mesh and seed each with a frag of coral. Let them grow and cut off for super easy propagation. I'm sure gsp will climp the Refugium walls too.
I think Gregcoyote has a coral scrubber, not too sure though.