I have a 55 gallon fish /invert tank with lots of live rock and live sand. I currently run a cannister filter and a skimmer. Do I really need the cannister. My rock is well established as well as the sand. I want to eliminate the cannister because I have a bad habit of letting the cannister go to long without cleaning, and feel I am just circulating my water through crap. I have heard the sand and rock are enough with a skimmer. anybody actually try this?