It works. I've used it, and corals, shrimps, snails, anemones all came through undamaged. It's a band-aid, though, not a real solution to the basic problem. Look for the big causes of cyano - nitrates, phosphates, and low low among others - to really solve the problem. But in the meantime, yes, red slime remover will temporarily kill off the stuff that's growing in there without any major issues to your inverts.