well we bought more snails...when that didn't work...we got lawnmower blenny, BUT E.T. prefers to eat the algae (brown diatoms) off the rock & the glass...does great job THERE...some people reccommend that you shuffle the surface of your substrate occassionly, but talk about labor intensive...earlier we had purchased a large CA hermit crab from LFS at $4...it will GLEEFULLY shuffle the surface of the sand, but only in it's path; could try to reduce time of lights on depending what you have in your tank or it MIGHT cycle & just die off eventually in to clumps