[mike31154]

Seems like it's just one of those things. Pretty well any type of power head or pump that moves sufficient water to keep a healthy reef tank is capable of mangling/shredding/attracting your critters. As mentioned, some pumps have optional foam covers, but they end up being a cleaning, flow robbing nightmare & I don't think many folks keep them on very long. I lost a Lawnmower Blenny early in the life of my tank to a Hagen power head that had an open intake. After that newb mistake, I added the large filter holder cage without filter to keep dumb animals away from the intake. Don't use the Hagens for flow any longer, now have VorTechs. Healthy fish can swim quite close & not get caught up in the pump. If my anemone were to drift in there, pow. Thankfully it stays put, but there are no guarantees. It's now so large that during the day when fully inflated, tentacle tips are getting quite close to the pump on the back glass. It runs at a lower speed, so for now, ok.

I don't sweat the issue. My critters either figure it out (stay far enough away) or they pay the price with their life. Haven't lost any to the VorTechs yet. Several years ago I topped up my CUC with some new snails & it was almost like they couldn't wait to slither into the front of each of my MP40s. I'm watching TV after fish tank lights out & hear this rattling sound. Snail had crawled close enough to the propeller to make contact. They all took turns doing this, not far enough to get chopped, but enough to make a helluva racket & put some wear on the tip of each propeller. I was a bit miffed, but no major harm done, either to the pumps or the dumb snails. After a couple of weeks of random occurrences like that, these slimy slugs finally figured out on their own to graze elsewhere. Once in a while I'll still see one on the outside of the wet side cage, but yeah, they stay away from the propeller now.

Sorry, long story, but my take on the whole thing is like the Darwin theory. I don't have any critters that cost more than my pumps, so don't sweat it if they decide to commit suicide. Replacement propellers are cheap though, I really should get 3 new ones.