Vinyl liner loosing water

[Flysurfn]

Hello all, this summer I was having to add water every 3 or 4 days. At the end of the season I let the water fall, to see how low it would go. It went down about 3 feet. Just above the light. I figured the light was the most likely the problem. Upon inspection, The light housing looks fine. I did try die around the light before removing it. The conduit inside the housing (where the wires come through was not sealed, but it is not leaking from ground water in reverse. I have a well point running to keep the liner from floating. I'm at a loss with the exception of main drain, or a plumbing issue.
I never saw any bubbles or anything oblivious for it to be a plumbing leak.
Any ideas

[Flysurfn]

Follow up- ground water is leaking into the pool from the bottom discharge fitting.
I ordered a new flange. Is there a sealant needed for the install? The flange has 4 screws to hold the vinyl liner to the fitting.

[CarlD]

Not sure I know what is happening. When you use the dye, do you turn off the pump and let the water go very, very still? The dye should collect at leak points. Last summer I was checking one leak and the dye collected on the floor and indicated another pinhole leak I was TOTALLY unaware of, now fixed.

[robbym70]

Not sure I know what is happening. When you use the dye, do you turn off the pump and let the water go very, very still? The dye should collect at leak points. Last summer I was checking one leak and the dye collected on the floor and indicated another pinhole leak I was TOTALLY unaware of, now fixed.

Don't mean to hijack the thread but can you tell me more about the dye method. My water level has gone down about 2-3 feet since closing. This happened before and I refilled upon opening with no abnormal loss during the following season so chalked it up to evaporation (which doesn't tabulate with me given the winter cover is on but...)

Anyways...I'll refill upon opening again but should do a dye test to find any pinhole or large leaks. Can you tell me more about the dye. Does it fade or how do you remove it after the test is concluded. Admins...feel free to repost in a new thread. Thanks.

[Flysurfn]

I think the plastic ring that seals the liner to the fitting in the bottom is my problem. I have ordered a new one. Im not sure if I can get the liner to match up exactly where it was to install it?

[CarlD]

AFAIK, the dye is harmless. You want the water VERY still so the dye will collect at the leak and you should have an idea where the leak is. But once it's fixed, and the water's moving, you won't see the dye.