How far to let leak drain?

[AndyT86]

I have a leak somewhere! I have been losing 2-3 inches per day. I have been reading all I can find on leaks here in the forum. I like Al's contraption for underwater patching, and plan to use it when I find the leak. I am going to get materials to fashion a dye dispenser tomorrow.

In-Ground 15x30, approximately 18,500 gallons, vinyl liner, 7 years old.

I have been letting the water drain, hoping to find the level of the leak. After several days the water is below the outer bezel of my light. There are about 15 inches left in the shallow end. The Main Drain and bottom of the stairs are the only places under water where the liner was intentionally cut during construction. I have not made accurate measurements to see if the rate has changed yet.

My question: How much further do I let the water drop without adding more water? I probably won't have much time to devote to using dye before the weekend. Ben has mentioned in the past that completely draining a pool can cause big problems. At this rate there should still be a couple inches of water in the shallow end this weekend. Will that be sufficient?

Thanks for your ideas.

[Poconos]

Thanks for the comment about the patch jig. Hope I never need it again. I think the rule is no less than 6" at the shallow end but that is only a general guideline. Personally I wouldn't let it get lower than it already is. I believe what will happen if you drain really low is the liner will stretch and start to tear where it is attached at the coping. Since you have a main drain I assume you have as deep end. Making accurate loss rate measurements can tell you a lot. As the depth of the water above the leak decreases the leak rate should decrease. If it doesn't then you have a deep end leak as was my case. I looked at this thread from March this year and I don't have anything else to add at this time.
http://www.poolforum.com/pf2/showthread.php?t=101
Good Luck.
Al

[CanuckPool]

Is it possible to empty the pool and attach the vacumn used when you initally install the pool vinyl to keep the vinyl stuck to the walls while you find an fix the leak and then refill it.

[waste]

Hi all, the amount you can drain from a liner pool safely depends (mostly) on how old the liner is. A newer liner (> 5 yrs) can have the water drained to ~ 2" in the sallowend and still not have problems, nor need a vac to reset the liner. Liners lose their 'stretch' over time and become more difficult to work with, however chemically abusing them will quicken the process. Another problem facing anyone trying to reset a liner in Oct, is the temp, liners are easier to work with when the weather is warm, the colder it gets the harder it is to 'play' with them.
Andy, I would recommend letting it go below the stair bottom plate, just to be sure that it's not the stairs, but no further, this would eliminate all but the MD or a tear in the liner (probably floor). For 2 -3 " / day it's gotta be something fairly large, if it's a rip or hole you may be able to see it from the deck (leaves or debris may get sucked into it thereby obscuring your view - use your brush to check any suspect areas)
Canuckpool, if the liner has enough 'flexibility' left in it, that's exactly what we do, so it can be done but in some cases, the liner still won't go back correctly (age or chem damage).
Andy, I wish you well on this and hope you can find and correct the leak! If I can offer any more advice, please feel free to ask (and if you don't, please let us know what it was and how you solved it )

[AndyT86]

Thanks for the ideas. Fortunately, here in central Georgia we are still playing peek-a-boo with 80 degrees, so I think my liner is still pretty pliable. I will let it get to the bottom of the stairs and no further.
I pulled my winter cover on a couple of weeks ago, so leaves are collecting on it instead of the bottom of the pool. (I fought that monster last spring.) Water is still crystal clear, I just have to pull the cover back to examine.
I taped a plastic ruler to the wall this morning, and I lost just under an inch in ten hours. So I figure still about 2 inches per day.
As for the dye, I talked to two different pool stores and they both said red food coloring. I stopped by a local scuba shop, and they didn't know what marker dye I was asking about (they recommended I go to the pool store ). Where do you get stream tracing tablets?

[Poconos]

Trying to spot the tear can be a dog depending on the liner pattern. As many times as I looked right at mine I didn't see it until I knew exactly where to look from the dye test. And this was with perfectly clear water. I scarfed my dye tablets from a GE chem lab years ago. I found ocean dye markers on-line and assumed a dive shop should have something but obviously not. I guess you would have to take them apart to get to the dye. Don't know how they are constructed. Food coloring is expensive. Something I've suggested over the years is raw beets. Chop them up and boil them and you have a concentrated red dye. Pretty cheap and you can make as much as you want...then eat the beets.
Al