I've never had any issues with my emerald crabs. As far as Nassaurrius snails go, they are great at cleaning up any un eaten food that makes it to the rocks and sand bed. I have about 20 in my 90g and 6 or 8 in my 30g. Mine breed like flies, but i don't have crabs eating them for thier shells either. Turbo snails crap twice for every bite they take and make a bigger mess then they clean up. I use a foxface for algae control along with regular water changes, and stong current. I have about 2400gph actual flow in my 90g, and around 800gph in my 30g. A midget with a small kayak would have a blast in my 90g lol. Fish poop is taken care of by the sandbed and the skimmer. The margarita snails will clean both the glass and the rocks, and i have never noticed thier poop all over the place like a turbo does. Not to mention how clumbsy turbos are about falling upside down and dieing. A large turbo dieing because he fell can cause algae outbreaks all by it's self. The only issue i ever have with my Margarita snails is that they like to go in the overflow, but they come back out and never had one hung up in the drain or show up in the sump. Asteas on the other hand, i have had clog the drain and cause a flood before. I only have one of those left in the display in my 30g, and a billion baby ones in the sump lol. The zebra turbo runs for cover at the first sign of light and stays put until the lights go out, but you can tell where he mowed the next morning for sure. He doen't poop twice per bite like a normal tubo either. They are always in the same spot every morning like clockwork in both tanks.
