Put a Rena XP3 on it... bottom is pre-filters... middle try fill with Seachem Matrix... top try get one of the oversize 7"x14" filter bags and put 500ml of Seachem Purigen. Use some of the Microb-Lift instant cycle to start your bio and you have a worry-free excellent filter system. I have really gotten into Australian Rainbows in smaller tanks. Really cool fish, something different. Can use some pool sand from Home Depot, rinse it well... Add some deco and have a very nice bow-front set-up.