I have always heard that you use a wet/dry for primarily bio filtration. When I built mine I designed it to do all three in one. Is there any definite need to have an extra canister filter for mech? My return pump was too big for my overflows, so I t'd the return line and put the extra pressure through a Mag 350 (pulled the impeller) with the micron filter. I also have two separate chambers in the sump that the water can't bypass that is running a coarse Poret foam, then a finer Poret foam. The water looks good in the tank, but I was just wondering if there is a need for more mech. The whole point of the sump was to get more bio and get all the hoses and cords and heaters out of the main tank. Thoughts?