I've just found out what I really didn't want to hear. That the sand sifter feeds off of the l/s. I have a 125 gal. tank with 3 1/2 inches of l/s and about 41lbs of l/r( I'll add more of both later). Is it possible to leave him in there without him doing too much damage? He's about 3 inches. I really need some type of clean up crew that is compatible with an aggressive tank. I know the lfs is going to give me a hard way to go about returning him. Despite how much money I spend in there.