Have a 250 gallon tank with 2 drilled overflow boxes in each corner. Each overflow goes through 3/4" PVC pipes down to my 55 gallon sump. Now the return compartment where the pump is will contain roughly 6 gallons on water (14"W 12"L 8"H). I will also have an FX5 running as well. I was thinking of picking up a Mag 12. Do you think that pump is to strong or to weak?