I HAVE A 150 GALLON TANK WITH 3 KORILLA 4 POWERHEADS. I CANT STOP THE SAND FROM BLOWING INTO PILES AND I HAVE BAREBOTTOM SPOTS IN THE FRONT OF MY TANK. I TRIED USING ONLY TWO OF THE POWERHEADS. I SET 1 ON EACH CORNER OF THE TANK AND HAD THEM FACING TOWARDS THE MIDDLE OF THE TANK. ANY THING I DO NOTHING SEEMS TO WORK CAN I SEE SOME DIFFERENT SET UPS YOU GUYS USE THAT DOESN'T CREATE THIS PROBLEM.