Hi. I highly recommend you change to pool filter sand.. your fish will love you for it. It is cheap, looks good, is very easy to clean and available from any Ace Hardware or pool supply store. My geos eat NLS pellets, Omega one shrimp pellets, tetra color bits as well as flakes... At feeding time they are like sharks in a feeding frenzy.. Rarely does food even make it to the bottom.. but if it does it is quickly scooped up.. They sift the sand 24/7 for left overs as well. You are just missing out on the best part of their behavior by not having the sand.. HTH Sue