Split from here
My Husband and I are having this exact problem right now. We bought this house 3 years ago which came with an old dream pool (wood walls vinyl liner). Last July we tore out the old pool, it had collapsed on the deep end. We put a new steel wall liner pool in with all new plumbing. We kept the old Polaris wth booster pump, and hooked it up to the new plumbing. It never worked great, but it kept the pool clean. End of last summer we noticed it sitting in one spot for half hr at a time. This summer it produced a drip leak at the pump (where the pump hose meets the pipe that enters underground) our pool guy repaired that connection and it seemed ok. We had also noticed a bit of vibrating of the pump. Last week we lost pool water down to below the skimmers. It was leaking about a half inch over a day when pool was shut off, it lost about a half inch when pool was running but Polaris line was not in use and plugged at the pool wall, and then it lost about a full inch within 1 hour when pool was running with Polaris hooked up. You can imagine our devastation seeing our brand new pool loose half its water. Over 2 subsequent days of leaving the pool shut off the water line leaked out and it had finally stopped right below the polaris return. There were no visible signs of an issue from above ground. The builder of the pool came out today and pressure tested all the lines, got zero pressure when tested the Polaris line. He capped it off at the pool wall, disconnected the pipe at the booster pump, and capped that pipe as well. We are filling the pool back up as I'm typing this and we are keeping our fingers crossed it holds. He recommended to never use the polaris line again, and to purchase a self contained robotic. The builder's opinion is that the risks involved with digging are not worth repairing the polaris line because in his experience polaris lines are very prone to issues. I am wondering if you have purchased a robotic, which one you chose, and how it is working for you?