hi gents and women just set up a 40 breeder . so the water level in the tank is right up to the top .right up there. so how do i lower it @ 1.5 or so below the rim of the tank.,,, do i lower the t/o system i took out 3 gal. the other day .and bingo it is back... .i would like to keep it lower then the top of the rim ..thank you