+1 ... IMO putting anything other than Macro Algae's in the refugium just makes it another display..All coral are technically filter feeders, problem with xenia use in a sump is they also compete for other nutrients and amino acids that other corals in your tank need to grow. Macro algaes in the sump compete for the same subset of minerals and dissolved organics that the algaes we try to prevent from growing require which is why they are more commonly used.
Give it a try and see what happens. I grow anthelia under a Par38 bulb in my fuge.
BUT, the most important question is...if it's in the fuge and the door is close and you cannot see it all the time, then is it still considered a display?
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