Another possible IG leak

Hi all,

We have been dealing the last couple of weeks with what we think is a leak. We have a 20K IG vinyl liner and in the last three and a half days we have lost about an inch and a half. I know that isn't a lot compared to some other leaks I have been reading about, but I have noticed a difference in the loss of water myself in the last few weeks, so I think there is something wrong.

Last night, we refilled the pool at about 8 p.m., and by 8 this morning, we had lost about a quarter of an inch. I also did a bucket test, and the loss in that was not as much as from the pool.

The first thing I looked at was the light fixture, as I noticed the cover was a little loose. It had been this way all summer though, even before I suspected we had a leak. We did the best we could to tighten that up last night after we filled the pool, but we still had some loss overnight.

I also looked around at the liner for some obvious tears or holes, and unfortunately, there was nothing that I could find.

One other thing to note is that the back edge of our property, about 5-6 feet from the edge of the pool, has been pretty wet. We have always had a drainage problem there because the way the property slopes up at the edge, but we have noticed it is a little more wet than usual. Just for background information, about three doors down from us, there is a sewer opening at the back edge of their property. (I don't know if there are any underground lines that run to that sewer or not.)

Even though I want to believe that wetness is from a possible sewer line, I have this sinking feeling the water is really from the underground return line to the far end of the pool. That return line doesn't seem to be producing dirt or dirty water, though. And the pressure is pretty strong as it has been all summer.

Oh, also the temps in St. Louis have been in the upper 80s the last week, but it feels a lot worse because of the humidity. We had a few scattered stroms the last two days, but those were hit or miss in our area. Just throwing that in there to see if those conditions can cause that much loss from evaporation.

I looked around at the pump and filter area, and there is a little bit of dampness on the pad, which is coming from the in-line chlorinator. That is hooked up in between the pump and cartridge filter.

Didn't notice any obvious cracking in the skimmer; but is there a sure way of testing that?

Any ideas? Many thanks!

!/2" a day may be hard to find. Was never successful at this when I was chasing my leak last year but at that damp area 6' from the pool, dig a small hole, let it fill with water if it will, then test the water for chlorine. Just maybe it will show some chlorine if it's pool water. May have to let the sample stand a little for the dirt and sediment to settle out. If it doesn't show chlorine, inconclusive. If the leak is in a return pipe then you won't get dirt in the pool because those pipes are under pressure when the pump is running. You can also try plugging the returns and skimmer for 12 hours or so and see if the leak stops. If it doesn't then my next step would be dye and if you get this far, post and I/we can dig up a bunch of posts on the techniques. You are already doing one thing right and that's making accurate measurements of the leak rate. Have you any idea if the leak rate is a function of the pump running?
That's it for now.
Don't get discouraged...you'll find it eventually.
Al
PS: Mine was 3" a day, 1000 gal/day. Good thing I had free stream water to keep it topped. And talk about discouragement and panic? Also a challenge to find and fix.

Thanks for the reply! No, I have not yet tried plugging the returns and skimmer. That will be my task for tonight. Hopefully that will help me narrow down if it is in the body of the pool or the piping. I'm not sure which one I prefer it to be!

Thanks also for the idea of testing the water in the backyard. We actually have a tiny puddle that has already formed in one spot, so there should be no problem in getting a sample.

I'll post the results!