I recently installed the Stevens ss57a 1/3 hp sump pump. It has the diaphram/pressure type switch. It works great, except for the fact that in each cycle, it seems to suck air for a second or so at the end of the cycle. It does not look like there is any way to adjust this switch. Is anyone familiar with this brand. It works, the noise is just annoying. I do have the "air lock" hole drilled between the pump and the check valve.