Leak in a vinyl lined in-ground pool.

[daytoman]

Ive got a vinyl lined in-ground pool. All returns and main drain is plugged,conduit in pool light is plugged.
The only things still under water are the light fixture and the main drain but its still leaking big time. I plugged the main drain yesterday and filled the pool to just under the returns, I still lost over an inch last night and it even moderately rains for a few hours. This is a 25,000 gallon pool so that seems like a major leak and its got me stumped.


SORRY FOR THE DOUBLE POST.

 

[duraleigh]

Welcome to the forum. :lol:

That's a tough one. You could let it leak down until it stops and that would be the leak level. The problem with that is if it's on the pool floor you do not want to drain your pool that far.

A pricey leak detection service may be your best bet.

 

[daytoman]

THANKS!
Yeah, I am thinking about letting it leak out until it stops..or at least until it gets to the bottom of the light, I'm not sure I could go any lower and cause the liner to start slipping?

The only leak detection I can find is American Leak Detection and its over $300 just to show up. But yep, it may be the only option. I just hate not being able to find it.

 

[duraleigh]

Often, a leak is a real PITA and simply can't be found unless you have the proper equipment.

I looked for a fairly small one off and on for 2 months and finally got lucky and stumbled across it. Let us know how it goes.

 

[Isaac-1]

Sounds like it is time to break out a squeeze bottle of food coloring and run the suspect sites with it, also check along seams and high traffic areas. Move slow so as to no disturb the water if possible (this is the big advantage of scuba gear for this sort of work, but it is not required, particularly if the lead is in the shallow end). With a leak that size expect to see a little mini tornado of food coloring that will disappear quickly, once you find it retest a couple of times, there is no mistaking the spot then. If in doubt it was probably just a eddy in the water from you moving the first time.

 

[daytoman]

Yep its got to be a pretty major leak. What also scares me is where is all the water going? Ive got a very sizable concrete slab around the pool so I cant see any wet or soggy areas in the yard. If it was a leak or tear in the bottom of the pool, I know I would see some type of erosion spot. This is crazy.

 

[Isaac-1]

You would be surprised how much water can go out a pin hole and how much can be absorbed into the ground.

 

[duraleigh]

I know I would see some type of erosion spot

Perhaps not. Water ALWAYS likes to go down if it can. It only comes up to the surface if it has no other subsurface escape route. Your soil or perhaps your backfill may be porous enough to drain a pretty large volume of water without you ever seeing it.

EDIT : Isaac beat me!

 

[daytoman]

By erosion, I mean in the bottom of the pool. The walls are metal but the floor is a soft concrete material (I'm sorry, I don't know the technical name of the material) Wouldn't that erode or get extremely soft around the spot if it was leaking through a hole in the floor?

 

[daytoman]

I'm gonna get in and try to dye test around the light and the main drain today, they are the only fittings under water at this point. If nothing shows up, im just gonna swim around and check every inch of liner that's still below water. That's about all I can do. I hope I can find it.

 

[daytoman]

I've lost another inch thus morning since I posted this thread wow.

 

[daytoman]

I looked all over the pool. There are no holes or splits. I tried dye testing the light and main drain but it was inconclusive. Looks like I'm going to have to hire it out...

 

[daytoman]

I wanted to get back on here and post a follow up.
It was holes after all!!!! Obviously I could not see them when they were still under water. But when the water leaked down and stopped, the liner stretched near the floor in the shallow end and low and behold there was a nice sized hole. Once I knew what I was looking for I found 4 other holes. I patched them up and the water held.

I just couldn't believe I could be losing that much water from a handful of little holes. But they were all right where the wall and the floor meet so I guess it flowed out pretty fast.