Yet Another Pool Leak Question

[ewtaylo]

Hello all,
I have been searching the forum trying to find help on determining the source of my leak. I have been able to take a few steps but I have a specific question that I need to ask. First some details:

I am working on the pool in my signature. This whole season it was loosing an inch of water a day which I was refilling. Now that it is time to shut it down I just let it go. It lost its typical inch a day until it approached the 5 penetrations (2 fiber optic light fixtures, 1 vacuum connector, 2 return jets). Once it was near them the rate slowly dropped. When the water level hit them the loss stopped completely. So I know my leak is from one of these items.

I sealed around all of them using 4200 and I refilled to one of my marks. Unfortunately it lost water at the same rate. I have now purchased 2 test ball and I removed the eyes from my return jets and I have them inflated to 40 psi in the the 1.5" PVC that feeds the returns. I will know the results of that test in about 3 hours when I roll back the cover and check out my marks.

As i was thinking about this overnight I realized if I could cover each of the penetrations with some sort of waterproof sheet then I could refill to one of my marks and remove the covers one at a time to determine which one is leaking. This should work because the pool surface is a smooth fiberglass. But what to use to cover the openings?

The best I could come up with was a square of 3 mil plastic sheeting sealed by duct tape. I could pump out water until it was below the penetrations, seal each opening, then refill. My question is if the duct tape would keep the sheeting waterproof for the 5 or so days it takes to test. If not is there a better way to completely seal the openings so I can eliminate each one at a time? Is there some sort of semi-permanent, submersible, tape product? Or something to seal the edge of the plastic to keep water from leaking through?

I appreciate any insight.

Thanks,
Eric

 

[ewtaylo]

Just a follow up. The test balls still had 40 psi in them and when I rolled back the cover the pool had lost water to the next mark. So the good news is that the 1.5" PVC line from the filter to the return jets is good. This does not eliminate the jet fixtures themselves. Moving a test ball to the vacuum line next.

 

[ewtaylo]

I decided to seal off each wall penetration. Then I will verify it holds water. Then I will remove them one at a time till I find the one that is leaking. I used 3M 4200 and some 6x6x2 containers purchased at Walmart. I let the caulk cure for 24 hours and now I am refilling the pool.

 

[prs]

If your caulk doesn't hold, you can get test plugs in various sizes at Home Depot.

http://www.homedepot.com/p/Oatey-2-in-Gripper-Mechanical-Plastic-Test-Plug-33401/100346775

 

[ewtaylo]

Ok, a quick update. Initially I was not using enough caulk to keep the covers sealed. I had water leaking into them. After a few stops and starts I finally got the pool to hold water for 24 hours. When I rolled the cover back this afternoon the level was exactly where I left it yesterday (used a sharpie to mark the level).

I have now removed one of the covers (the vacuum line). Tomorrow afternoon I will check to see if the water level has gone down.

I have been able to remove all of the 4200 caulk from the wall of the pool. I use a straight edge razor blade to get down to the fiberglass and then a nylon dish scrubbing pad to get the last part of it off.

 

[ewtaylo]

Ok, the issue is isolated to one of the return jets. And it is not the pipe leading to the jet. Right now the pool has not lost any water and there is a test ball in the pipe and a plastic cover sealed over the jet. So this leads me to think there are three possible leak sites:

1) gasket between pool wall and jet
2) cracked jet
3) dry PVC joint where the 1.5" schedule 40 attaches to the jet.

I am thinking the most plausible is #3. I covered #1 by using 4200 caulk around the jet at the beginning of the whole process. Caulking all around it had no effect on the leakage rate. #2 is possible but I didnt see anything cracked when I inspected it when the water level was pumped out below the jet.

So I can see the end of the PVC pipe on the inside of the jet when I remove the eyeball. I am thinking of draining the pool below the jet and then drying out the joint. Then I will smother the inside with PVC cleaner and let that dry. Finally I was planning on doping the inside of the joint with PVC cement.

Does anyone have any tips on sealing a dry PVC joint from the inside?