Leak in pool...does this wrinkle look like it's to blame?

[pbsry]

Evening, all. I'm brand new to pools, and I've been lurking and leeching off your collective expertise on the chemistry side for a couple months. Now I come with something more specific:

I bought a house in the winter with a ~35,000 gallon, in-ground, L-shaped vinyl pool. It held water over the winter, but once the weather got warm (i.e., 90's) I noticed a leak that has gotten worse over the past few weeks. Now, I'm probably losing 1"-1.5" a day.

Yesterday, I noticed this big wrinkle below one of my skimmers. Pardon the night shots, but using the directional illumination of a flashlight was the best way I could find to highlight the texture.

I can't find anything else that looks suspect, and it leaks at the same rate regardless of whether the pump is running or not. I'm not sure how old the liner is, and I don't know what kind of construction the underlayment is. I'm in north Alabama (Rocket City, USA!), so we didn't have very bad freezing over the winter, and it's leaking down to below where the winter water line was anyways.

So, questions:
1.) Does that wrinkle look like it would cause a leak that bad?
2.) I'm going to try a dye test tomorrow. If that is the problem, is there any hope to fix it?
3.) Out of curiosity, how do I figure out what is underneath my liner non-destructively?
4.) I've read that it can be dangerous to allow a vinyl pool to drain too low...depending on the construction. Does that sound right to y'all?

Thanks for you help!
pbsry

 

[PoolESQ]

Since your water loss coincided with the increased temperatures, are you sure the loss is not due to evaporation? Pools can lose a lot of water when the temps get in the 90s. Before you go pulling your liner apart, I would perform what's called a bucket test. You can search for the procedure on this forum. It basically involves putting a certain amount of pool water into a bucket and marking the level. Put the bucket on the pool stairs. Wait 24 hours and see if the loss in the bucket matches the loss in the pool. If so, there is no leak, and you are losing water due to evaporation.

 

[duraleigh]

1-1.5 daily loss is not evaporation. You have a leak. It appears water may have gotten behind the liner at some point and caused that wrinkling.

1.) Does that wrinkle look like it would cause a leak that bad? Not sure the wrinkle is the issue
2.) I'm going to try a dye test tomorrow. If that is the problem, is there any hope to fix it? See below before you do the dye test.
3.) Out of curiosity, how do I figure out what is underneath my liner non-destructively? You will when you find the leak and start the fix...probably steel wall.
4.) I've read that it can be dangerous to allow a vinyl pool to drain too low...depending on the construction. Does that sound right to y'all? Yes, ANY pool requires caution when draining completely.

Why don't you, as a first step, allow the water to drain down as far as it will. When it stops draining down, your leak should be at that level.

 

[danpik]

Duraleigh has given some great advice on finding the leak. The, let it drain down till it stops, method is how I found the leak in my above ground pool a couple years ago, Unfortunately the leak was in the floor. Anyway, that is a good way to at least confirm the area you suspect. I would suspect it is the area around the skimmer opening more than the wrinkles themselves.

As far as draining pools being bad,... There has been a lot of, shall I say, Fear mongering, about this. some will have you believe that the apocalyptic end of the world will happen if you drain it. The truth is, using proper precautions, any pool can be drained successfully. You need to know what the ground water situation is like in your area. Right now, with the Ark building rains we have had near me, I would not drain an in-ground as the liner will definitely float or in the case of a concrete pool the whole pool will possibly float . As for liner shrinkage, if the liner is fairly new (couple of years) you may be good for a few hours to a day before you need to get water back in.

As to what is behind the liner... it depends a lot on the age of the pool. Most likely though the vertical walls are steel and the bottom is either sand, vermiculite or a combination of the two

 

[pbsry]

Thanks for the advice, gents. I have some friends coming over to swim on the 4th, but after that I'll stop adding water and see how far it drains down.

@PoolESQ: I forgot to mention, but I already did the bucket test for evaporation. Definitely a leak, as duraleigh said.

@duraleigh & @danpk: Since I live in a bit of a valley and my soil always seems a little bit...damp...I'm going to assume I have a fairly high water table...where can I look that up?

If it happens to be the area around the skimmer opening, how does one go about fixing that? If this were a window or sink, I would throw some clear silicone caulk on the joint...