Help with a pin hole leak!

Two years on the outside of this forum, first post. You guys have been great so far, but I need direct advice this time. I have an above ground pool 52" wall height, that is sunk half way in the ground. 15,000 gallons or 18' X36'. We love it and you all have made it so easy. It is our baby during summertime for the last three years! Anyway, this winter we notice that we have a water leak somewhere. We lose water at the rate of 1" per day, or about 320 gallons if my math is right, but the wierd thing is that once it get to "ground level" or the water is two feet deep, it doesn't leak anymore. My best friend is just sure that the leak is in the side wall where is stops. I searched everywhere on the top two feet of the side wall and found nothing. Question one: Could a leak that small with my configuration need the pressure of a full pool to "push" the water out of a pin hole leak? Or another way of asking could the leak be in the floor? We installed a poolcrete hard bottom, or protland mixed with vermiculitte, ourselves and although Im happy with it it is far from perfectly flat.
Question 2: In detail how would be the best way to find this leak:what kind of dye, How to apply it, Ect.

Thanks on this one, my wife is finally a believer of the forum!
The Nolans

IMO, your leak is bigger than a pinhole. When I drain the rainwater out of mine in the winter, it takes about 2 days to drop 6 inches siphoning through a garden hose. Look for something going through the pool wall at the level the water stops: Return, light etc. If nothing there, check the seams first.

If you have a main drain in the flloor, I'd be guessing you have a plumbing problem, maybe just a leaky valve.

Well , I don't know then?? One thing I forgot to mention. All the plumbing is new this year, and also because the leak was detected during the winter and was below the skimmer and return, the plumbing is not the issue.
That is one of the reasons that I'm stumped:confused: I should be able to see the hole right?? I just returned from the store with some RIT Liquid dye(Will this stuff work?), and some goggles, and Im going in!! The water is still a little chilly here 73 degrees, but no pain no gain. If a seam ripped that would make sense, it would camoflauge itself, not be a gapping hole! Any other suggestions?

If you don't have a main drain, then I think you can safely assume plumbing is not the problem. I wouldn't use the Rit. I'd go with food coloring in a syringe. Put a piece of tubing on the end and inject a drop or two near the level the water stops leaking, starting at the seams.

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Originally Posted by chazzilla

Well , I don't know then?? One thing I forgot to mention. All the plumbing is new this year, and also because the leak was detected during the winter and was below the skimmer and return, the plumbing is not the issue.
That is one of the reasons that I'm stumped:confused: I should be able to see the hole right?? I just returned from the store with some RIT Liquid dye(Will this stuff work?), and some goggles, and Im going in!! The water is still a little chilly here 73 degrees, but no pain no gain. If a seam ripped that would make sense, it would camoflauge itself, not be a gapping hole! Any other suggestions?

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I wouldn't you RIT dye! You can get phenol red at the pool store, or as stated, food coloring.

I taped a long thin piece of auto vacuum hose to a 1/2" PVC pole and the other end of the hose to a garden sprayer. You have to go very slowly, positioning the hose near the target, then giving a little squirt of dye, and wait. The 320 GPD works out to be a little less than a quart a minute. May be tough to find. Mine was about 3 qts per minute and found it fast. To see if I could see it suck the dye I started a siphon with a garden hose on the bottom and set the rate to that of the leak then played with the dye to see what it looked like, and, if I could detect it. For the dye I used red stream tracer tablets dissolved in water. May also find a dye marker at a dive shop, or, go buy some raw beets, chop and boil them, make a lot of red beet dye, then eat the beets. Oh, one other thing. With a leak that slow you may have trouble with turbulance just from you being in the pool. Water has to be very still. When I was doing mine last year even the sun heating the water was enough to cause noticable turbulence in places. Water has to be very still.
Good Luck.
Al
(ajs-1)

I finally gave up on the dye and found two holes just by dragging my foot along the bottom. One hole is slightly bigger than a pinhole, and the other one is bigger but not real big. Patched them up, so we will see tomorrow. I think that is what was happening, the holes where so small that I dont think the dye was doing anything! Anyway, thanks again guys, If I run into anything else I will shout back at you.