Does anyone have any experience with using a sand substrate? I have had this black sand in my tank for about half a year. It looks real good, but I am having huge problems cleaning it. I have been using the gravel vacuum to clean poo that is sitting on the top, but I'm afraid stuff has been getting buried and causing problems. I recently checked the ammonia levels and they are way way high, and the only thing I can think of is that it is the sand. I am going to go to the lfs today and get a mess of ghost shrimp to see if they can help clean things up a bit (in addition to the 11" pleco that is in there). I'm moving in about a month, so I'll have to take the tank down. Should I toss the sand and get regular gravel? Thanks.