I am in the process of selling my 6-7 inch red devil and 8.5-9 inch jack dempsey. I currently have 3 baby red bellies ready and waiting for their new tank. I am thinking of switching from gravel to sand when I put the P's in. I am wondering how much do I need to worry about sand killing my penguin 350 biol wheel filter? Do I need to take any steps to make sure it wont happen? If anyone has alot of experience or horror stories with their non-canaster filters please share them with me. Thanks.