RedEDGE2k1;540077 wrote: Not true at all. I had two MP40s on my 90 for 2 years, with 3" sandbed. Both pumps were set to Reef Crest mode, which ramps up to 100% power and back down over time. No sand problems.
You also said you can't stand the noise of Vortechs; the pumps in your experience must have been misaligned (dry wide to wet side, through the glass). Like Jeremy said, my Vortechs are silent unless I shove my ear against the tank.
Dustin