So ive been having no outlet pressure to both pool and spa. When I put valve to just pool skimmer it has good suction, but half way primes and 0 filter psi. Since i have good suction dosent that rule out a "suction side" blockage? could there be an issue filter? if there were any kind of leak wouldnt it be leaking water because its on the "return" side?
What is that plug for? and am i supposed to have one installed in hole on other side?