My flow to the pool has dropped to almost zero, even after cleaning and replacing the filter. PSI on the filter tank reads 16, which is just below the "start" mark and well below the "clean" mark, so the problem is elsewhere. Where is the pressure sensor on the pump itself? Does it just sense the torque in the impeller? Trying to figure out if this is a clog on my suction side down the line from my skimmer basket, or something in the pump itself. Can I use a normal plumbing snake through my lines from my skimmer port to the pump? I tried blasting water through it with a hose but couldn't get a strong seal.