As some of you know, I recently moved out of state and had to sell the 300g. I now have a sad little 55 freshwater tank and am looking to add a canister filter to it. Tte tank will be overstocked and I want to have as much filtration on it as possible, without overdoing it, of course. I currently have 2 x Marineland Penguin 350 HOB's on the tank. I have been looking at adding a Fluval 406 or an FX4/FX6. What do you all think? I will be upgrading this system to a 75 or 90 in the next 6 months or so, so the equipment will be used on that as well. Your thoughts are appreciated.