Locating leak - help

[samtex]

I have a fiberglass walled, gunite bottom inground pool. I have had a leak for some time which causes me to loose about 3/8" of water per 24 hours. The leak isn't affected by whether or not the pool pump is running. Evaporation isn't the issue either.

Last week I decided to get serious about locating the leak, I decided to let the water drop until it stopped, thinking it would help locate the leak or at least the level of the leak. The leak continued each day, so I decided to speed it up, thinking the pool light might be the issue. Sure enough when it got to the level of the pvc connection behind the light, the water level stabilized. I used some epoxy putty from the pool store, thinking my problem was solved. I added some water until the pool light was covered and waited, the leak seemed to be fixed. I went ahead and refilled the pool, the next day I noticed the water level had dropped again. Using the same method as before I let it drop on it's own, until it was below the skimmers and the return lines. I pumped more water out about 2" each time and waited. Finally the water stabilized again, about 3" above the pool light. So it seems the first leak was fixed.

I figure the leak must be somewhere close to the water line, where the water line stopped dropping. I used some leak dye to check for leaks. The walls of my pool are fiberglass panels, each about 8' in length. The are bolted together from the backside with some type of gasket material between panel. It appears to be a silicone (?) type of gasket. There are no other fittings etc. at the suspected leak level. I added an inch of water to the pool and checked each gasket seam as well as the steps area. So far no luck it finding the leak.

Could the leak be so small that the dye isn't effective in locating the leak? Any suggestions?

samtex

 

[Texas Splash]

Hello and welcome to TFP! So if I understand correctly ... after fixing the light niche leak, you believe you still have a leak somewhere above the light but below the skimmer and returns. Is that correct? Before you repaired the light area,, you estimated about a 3/8" drop per day. I would assume the water loss is much less now right? No chance the post-repair water drop could indeed be from evaporation? Have you already done the bucket test to confirm? Also, no main drain I'm assuming?

 

[samtex]

Not from evaporation, I checked that with a plastic container, plus when it reaches a certain level, it stops dropping. I do have a main drain but the water stops dropping before it reaches the light, so I can't see that it would be the main drain. That is correct, the leak appears to be below the skimmers and returns.

The leak did seem to decrease after patching the light niche. It was dropping about 18 mm per 24 hrs to about 10 mm now. I may have underestimated the drop originally when converting to inches.

Samtex

 

[samtex]

Update, I located a loose piece of caulking on the second step (wall). A applied epoxy putty to both sides of the step. The pool still drops but is stopping about an inch above the previous level. To summarize, I appear to have found two leaks so far. One behind the pool light and one on the entry steps. Each time after applying putty to those areas, the level has dropped but to a higher level than originally.

I have calculated that I am still loosing about 100 gal per 24 hours if I raise the water level to the normal level. My current issue is that after inspecting all around the pool wall at the current level where the dropping occurs, I don't see any obvious place for a leak.

Samtex

 

[Texas Splash]

Wow. Your situation is like a Warner Brothers cartoon where a character plugs-up one leak and two others appear.

 

[samtex]

Hey, at least I'm loosing less water. Another leak thread on this site made me reconsider the main drain line near the pump possibly. Wonder what it would take to plug the main drain??? hmmm

 

[Texas Splash]

I saw that one too. At this point you don't rule anything out. I hope you find it.

 

[samtex]

Well, we have been having plenty of rain lately. I went out Friday after we got a bit of sunshine and noticed water running INTO the pool from a skimmer (Water level in the pool was about 4 inches below the skimmer). Turns out the water level in the yard was pretty high (Water was standing in places).
So I got out the putty and sealed the third leak (Not the one I was looking for). I did know the pool level would drop rather quickly after a big rain and the pool never would overflow. The leak was about an inch or two above the bottom of the skimmer.

Hopefully over the next few days we will have enough sunshine that I can check the main drain line.