Ok, so the return pump is not pushing enough water back to the tank compared to the overflows draw from the tank. You can try to reduce the distance the pump has to return the water (vertical distance) or you could get a larger pump. I am not sure why the pump is making a huge sucking noise unless the water level in the sump is not high enough to cover the pump completely then you will be getting a lot of tiny bubbles in the tank which is not good either. Hope this helps! |