Been lurking for some time but finally I must post! I've got a small fiberglass pool with an attached spa. I'm not 100% how the spa is plumbed, but there are 6 jets, with "air port" on the deck which you can open to induce air. I'm getting very low pressure from these jets, to the point where they aren't pushing hard enough to aspirate via the port. I can see the first 2 sputtering air, and hear them "chugging" in the deck port. I can't say for certain I'm getting equally low pressure on the pool side, but I believe I am experiencing loss here as well, it's just not as obvious. Filter pump shows 22psi when diverted to pool return, 26psi to spa for what it's worth.
There are only 2 suction lines, 1 from the skimmer (pool), and one from the spa (shared to 2 ports in spa). Changing between the 2 does not give me any noticeable pressure change in the spa. I've tried for weeks to troubleshoot this and have run out of ideas. The only access i've gotten to the plumbing is removing the Turbo Cell thus far. Attaching a photo with reference points in case anyone would like to assist. (please excuse the weeds )