I have a 80 gallon tank which I aquired with a older Eheim 2217 canister. I am very happy with it so far - runs quiet and has good flow. I have been reading about flow rates and filtration. It sounds like I might be a little under filtered for a tank this size, so I am thinking of adding a second canister most likely another 2217. A couple questions: - Is it a good idea to add a second filter and if so would another 2217 be a good choice? - What is the best way to set up the intake/outflows in a dual filter setup? Should the outflows be on the back aimed forward? Or at opposite ends aimed inward, toward each other? Right now I have the intake near the bottom about 3 inches in from the back right corner; and the outflow is on the left end spraying accross the tank positioned a couple inches under the surface aimed slightly up as to cause a ripple effect at the surface. I have fake plants and decorations now but would like to move towards a planted tank sometime in the future. I appreciate any experience/wisdom you have to share. Thanks in advance!