how, i was wondering what kind/strength of power head i would need to be able to return the same amount of water to my tank as the overflow box is removing so the main tank and sump are in equillibrium. my tank is 100 gallons and the sump is gonna be a tal 30 gallon that im just gonna stick a skimmer and heater and maybe some live rock in. from the top of the tank to the sump it is a little a less than three feet.