Pesky leak

[swreeder70]

Looking for some advice on finding a leak. IG Pebble-sheen pool with a spa. I noticed earlier in the year that it seemed like my auto filler was not keeping up with evaporation. After playing around with it, I realized the pool was leaking water.

If I shut everything off, and let it sit overnight, the pool drops by 1". The Spa level does not change. I let it sit for over a day and the water level dropped 1" below the skimmer inlet. Today I got in the pool with a syringe and leak dye. Checked all returns, drains, and light fixtures and the dye did not indicate any leaks. Scanned every nook and surface of the pool for any physical signs of damage with nothing detected.

I would think that with the water 1" below the skimmer entrance, that the skimmer boxes and skimmer return lines are good. I'm going to pull the light fixtures tomorrow and check with dye inside the housings, but doubting I will find much since no dye pulled in around them today when I checked.

Any other tips or tricks for finding where my water is going?

 

[Texas Splash]

Just to be sure about a leak, has it been windy in your area? Strong winds and hot ambient temps will pull a lot of water. Figured I'd ask. But if not, then the water drops with system off could be on either side (suction or pressure). You could try (with system off) plugging one side or the other to try and narrow down your search. Otherwise, it is possible that you have a small leak either behind a light (in the niche) or deep in a suction/return line, and it's just not strong enough to pull the dye. So if your light niche inspection reveals nothing, you might have to have a company pressuring the system and listen for the leak.

Last thought, do you have a multiport valve on your DE filter? If so, check your waste line exit to make sure your spider gasket isn't allowing water to exit.

 

[swreeder70]

I figured it out, simple fix but took a while to track this one down. So what was happening is the auto fill valve was never fully closing, It had small bits of gravel stuck in the valve. At night when we typically run dishwasher and laundry, with that valve being semi open, it would cause the backflow pressure relief valve to pop, due to enough negative pressure being created in house due to the water draw. At that point water was free to flow backwards to the point of the relief vale and drain water. The pressure relief is located at the corner of the house, away from the pool plumbing and I never noticed it being wet there.

I flushed out the refill line (amazing the amount of gunk that washed out, was properly never flushed after construction), installed a new float valve.

Pool held water all night, just turned on the auto fill vale and all is good.

 

[Texas Splash]

That's a great catch. Gotta remember that one on future troubleshooting. Might be a good idea to add autofill to your signature as well.

 

[DB-Cooper]

Well done tracking it down!