I recently changed to sand in my aquarium. I used white play sand. I put prefilters on my aquaclear 110s, because I had read sand would ruin them. I didn't put a prefilter on my reba xp4 or fx5 though. I'm curious if I need to do that. I had noticed sand on top of my powerhead that's under the spraybar for the xp4 so some might be going through. Thanks.