I rake my sand bed every few days....stops any buildup and keeps the sand moveing.......No need to vacume it at water changes...in the sea on a reef the sand is constantly moving with tides.....I love the different ways the sand moves around constantly changing ......and my wrasse helps.....he's always grabbing big mouthfulls of sand sifting through it looking for food...my (berlin) protein skimmer also LOVES it when I rake my sand.....lol....If we could get crabs and other critters to burrow down and clean our sand beds we would ALL be a lot happier.