My Main Drain line appears clogged. Pump only recieves water from skimmer. When divert valve is switched to M.Drain line, all flow to pump stops. I bought a bladder type pipe unclogger and regardless which pipe it is put in, water will not flow backwards (as in pushing clogs back out through main drain). Weird thing is, although skimmer line works fine, When bladder is inserted in it to push water backwards to skimmer, the flow will not go. I mean roughly 100psi will now fow back through skimmer. Only forwards. My question is- could there be check valves in these suction lines since the one skimmer line only flows one way? The only other thing I know to do is unscrew drain cap 6 feet down and insert bladder there and try to push clog forwards to pump.
Any ideas how to unclog my main drain? And thoughts on why water only flows towards pump on skimmer line?
