I have a 210 gallon with two FX5's and am very happy with the filter. I cant stand the hoses, intakes or outputs. I did custom black PVC spray bars with the heavy vinyl tubing, and will probably soon make up my own intakes. That is my only real gripe with the filter. I wish in line heaters were cheaper for big tanks. I ended up custom plumbing two of the Hydor 300watt into one of the outputs of one FX5 and it works fine. I personally would not mix a bunch of different filters. It is much nicer to have lets say three of the same model/brand so if anything happens you can rob form one to keep another running if necessary, but thats just my opinion.