Leak in liner?

[AnnaK]

Last year toward the end of the season I noticed a damp spot on the ground near one end of the pool. Not wet, not squishy, just damper than the surrounding area. I sort of set that aside in my mind since we were near closing.

We opened and refilled in mid-March. Once all the snow and ice were thawed and the ground had dried I began to notice that same damp spot. Moreover, I seem to be losing about 1" every 36 to 48 hours as measured by the water level against the skimmer housing screws. I just cannot attribute that much water loss to evaporation.

The water is crystal clear and the bottom is spotless. I cannot, for the life of me, see a tear or a hole and there are no wrinkles on the bottom. There are some uneven areas where the sand has shifted and where dirt collects.

The pool steps aren't in yet but we'll do that this weekend.

How can I find out whether there is a leak and where it is? The water isn't warm enough yet to get in. I figure we could put on goggles and snorkel our way back and forth inspecting the bottom, but it'll be another month at least before we can do that.

What is this test, it uses a bucket, I think, where you can check for evaporation or loss due to a leak? I also seem to remember something using food coloring dye - how does that work?

Anna

[Poconos]

Finding small tears can be a dog depending on the liner pattern. Several years ago I developed a leak that I ultimately found at the deep end where the floor blends into the wall. Three small slits. Have no idea how they got there. Could not spot them from the surface initially but once I found them I could identify them.
For the bucket test you put some water in a bucket or a pan or something you can fill with a few inches of water. You want it riding low in the pool water so you don't disturb air currents and tie it so it stays in the middle somewhere. Measure that water level and the pool level accurately and see if there is a difference after some period of time. Last year I chased what I thought was a leak again. Almost an inch a day at the worst. Later stopped. I attributed it to relatively warm water and cold nights and low relative humidity. Drove me nuts for nothing. You have a different case in that you see dampness.
For dye I have some fluorescent red dye tablets that are used for stream tracing or similar applications. You can probably find dye markers at a dive shop and one should be all you would ever need. Also you could boil raw beets and use the juice. A lot cheaper than food dye. I use a small garden sprayer with a long piece of auto vacuum hose jury rigged to the sprayer nozzle with silicone seal and the hose is taped to a 10' piece of 1/2" PVC pipe. Lets me reach the depths. You have to go real slow so as not to disturbe the water and let out little squirts of the dye. If you get within a couple inches of the leak you should see the dye sucked in. In preparation for patching find yourself a can of Boxer-100 vinyl cement. Most pool stores should have it. This is a slow acting cement and won't curl the patch on the way to the bottom. A lot of cements are so aggressive the patch starts curling immediately and makes placing it difficult. If you can do it with your hands it's a lot easier. Otherwise I have a technique I used at the deep end that worked well. More on that later if needed.
Al

[waste]

AnnaK, always good to see you:) Sorry that this time it's a problem in your pool:(

Al's given you great advice, so I can't add anything else - except to say that we'll stick with you through this until the missing water is found (or at least it's cause :D )

Luv & Luk!

[AnnaK]

Thanks, you guys.

Spent yesterday afternoon in a panic. Not about the pool but because I could not access Pool Forum. The site simply would not open. I was afraid it had gone down entirely and what a travesty that would be!

Al, thanks for the description of the leak detector apparatus. It sounds like a project I could totally get behind.

But first, the bucket test. Once I have water in the container and have it floating in the pool, I mark the inside of the container with its water level and make a mark outside the container for the pool's water level, is that correct? Evap would affect both the same and if I do have a leak the mark on the outside would indicate that.

Ted, I appreciate the encouragement. Did you say you had put in your garden already??? We're still getting night frosts here :(

Anna

[Poconos]

You have the bucket test right. Would be interesting to know the actual leak rate. Ignore the fact some loss is due to evaporation and start to record the level and time as accurately as you can. On your 12,000 gallon pool if you assume a 48" water depth that relates to 250 gallons per inch. I thik my rate was around 40-50 gallons per hour but I'd have to look at records to know for sure. That was easy to spot with the dye.
Al