I installed a Waterguard Radon Aerator. It involves a sprayer and a repressurization pump(submersible 1/2 HP in sprayer tank) and output pressure tank/pressure switch. Output gear similar to well pump equipment. The problem is a loud thump sound every time the pump turns off. Loud enough to be heard in much of the house (unit is in basement). Pressure tank at 38PSI precharge. Pressure switch was at 60/40. Tried lowering to 55/40 to see if noise affected. No change.

Any advise on noise abatement? Is this noise normal in a well pump with the noise not heard because it is too far away or is this something that can be improved with some adjustments to setup?