I'm changing the sand in my 140g. The 140g is home to 5 Frontosa Burundi, 1 Synodontis Eupterus, 1 Synodontis Hybrid, 1 Synodontis unidentified, 3 striped raphael catfish, and in the future possibly leleupi, Neolamprologus Brevis, Cyprochromis Leptosoma and other smaller Tanganyika Cichlids. ( I know there is a chance that the Frontosa Burundi will eat the smaller Cichlids.) my question is what sand size would be best here. I can get poolfilter sand, but Im afraid it might have sharp edges or something.