A challenging leak

[simicb]

I have a recently replastered, in ground gunnite pool. It measures 15' x 30' and has an attached jacuzzi. It looses about 7/8" of water in a 12 hr run cycle. It does not leak when the pump is not running. (bucket test) If I set the valves to draw water from the jacuzzi and return to the pool it does not leak. If I draw water from the pool and return to the pool or jacuzzi it leaks. I have hired a leak detection company. They have pressure tested the return lines and suction side lines and swear there is no leak in the plumbing.

I have applied epoxy in the small joint between the skimmer and tile. This had no effect on the leak. Also the skimmer is a copper/plastic combo unit that I think was common in the early 1980's. The leak detection guy suspected that the skimmer was leaking at the joint between the copper skimmer bottom and the plastic side walls. I applied epoxy to this joint and the pool did not leak for two cycles. Then I came home yesterday and the pool had lost about a 1/2" of water in 13 hrs of run time.

I happen to remove a fence post near the pool equipment pad to inspect the pool pipes for a break in that area. No dice. The pipes are fine. However the resulting hole begins to fill with water while the pump is running, the results of the leak I described above. There is no obvious source for the water acumulating there, however it is in close proximity to the skimmer, about 6-8 feet away.

The leak detection guy is about to bail on me. He has been there four times and no solution yet. Any Ideas?

Thanks.

[ChuckGeo]

I would suggest an additional set of water loss tests. Specifically, on the first day set the valves so the pool skimmer, main drain and return valves sare open and the spa return and main drain valves are closed, mark the levels in the spa and the pool and run the pump for 24 hours then measure the loss from the pool and spa. Note the loss as pool on and spa off. Second day set the valves for spa operation (do not turn on the heater). Mark the levels in both the pool and spa and again run the pump for 24 hours then measure the loss from the pool and spa, noting the loss as pool off and spa on. Let me know your results.

[Barolac14]

Repair it with some strong chemical material which reluctant to leak water from pool.
Water proof cement consider best for this purpose.
I also was face this type of problem and hire pool instructor to find out better solution. He said use water proof cement at the point of leakage.

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