ok so i was going to upgrade to a 90 gallon tank. i have a 30 now. i was thinking of doing half the tank with sand and the other half bare bottom. the reason i am thinking of doing this is because i have a yellow gobe and i know they need sand. i dont real want to go out and buy lots more sand as it will most likely start a new cycle. i also like the bare botton tanks. does any one do this and if so can you post photos and let me know your experience. thank you