Timmie, any chance that the noise you are hearing is from the water breaking the surface? - if so, point the eyeballs down a little. I think the red handle you are talking about is on line coming into the front of the pump, if it is you don't have to change it to backwash the filter - it's there to adjust the flow from your 2 suction sources (like for vacuuming) or keep the prime in the pump when you empty the strainer basket in the pump (if the pump is significantly higher than the water level)

HTH