I have indeed tried them before. They do indeed eat aiptasia, but they have one major drawback, they do not function well in most mixed reef aquariums because they either get thrown around too much by fast moving powerheads, or get eaten by fish, hermits, scavengers, whatever. When I put 4 of them in a "sterile" tank with only LR that I use for QTing corals, they massacred the aiptasia on the rock overnight. Once I trasnferred them to my display tank, they got eaten and never seen again... So unless you're prepared to QT all your fish, shrimp, crabs, etc and drop your pumps to a lower flowrate for a while, they might not be the best thing.