I've been losing a lot of water recently. I replaced the four year old mulitport valve & the base gasket & was still losing water. I set a bucket on the steps, filled it to the same level as the pool, set it on the steps & let the pool run. Sure enough, the bucket water level was about an inch higher than the pool level after about 24 hours. Tried it again with the pool off...Still losing water. I assume then that my four year old liner has a leak. I call a company that guarantees they'll find the exact location of the leak leak & they're coming out today ($450.00). Friday night, I filled the pool back up to operating level like they asked & made sure everything was running fine. While doing this, I noticed that I didn't fully tighten a few of the screws holding on the multiport valve. I tightened those & my water level has maintained the same level since. Tried the bucket test again & didn't see any difference between the bucket & pool.
Would a leaking multiport valve siphon from the drain? The water went below the skimmer, so it's not there. I used dye to check all jets & the drain, but didn't see anything. I'm still having the leak folks come out just to put me at ease, but is it remotely possible I fixed it? Or, that it would leak when turned off? It just doesn't make any sense.