Spa loses water when not running

[lttsai]

I have had a leak since August and have hired two leak detection test companies. The spa loses 1/4 inch of water an hour when it is turned off. Pressure tests were done on the pool and spa. The Ortega check valve and spa fountain check valve have been replaced. Both three way Jandy valves that control the spa and pool were replaced but I kept the old housing intact so I wouldn't have to hire a plumber. The water in the spa drops below the spa return jets and below the level of the water in the pool. Initially the spa was losing 1/2 inch of water an hour, but epoxy was applied to the spa light conduit and that cut down on half the loss. The water does not appear to be going into the pool. Any suggestions would be greatly appreciated.

[ChuckGeo]

Does the spa loose any water when it is on, in spa mode? If so, at what rate per hour? If the water loss is only when the spa is off, with the valves in spa mode, the suspicion would be the spa venturi air line. The same loss on and off indicates something othe than plumbing - still leaking at the light conduit, around a return fitting or the light niche aor in the main drain sump. Greater loss with the pump on is indicative of a leak in the return line.

[lttsai]

Thank you for your reply. I need some additional clarifications since I didn't understand all the terminology.

Yesterday, I ran the pool for 24 hours with the spa return jets turned off and the spa fountain partially turned on; the pool dropped 1/2 inch.

Could you let me know what the spa venturi air line is? The leak detection company pressure tested the spa return jets as well as the three holes at the bottom of the spa. One hole is the spa fountain and the other is the spa drain. Is the third the spa venturi air line?

If the spa drops below the return jets then does that rule out the spa return fittings? is the light niche where the spa light rests? When I initially turned the spa off and let the water drop, it dropped at a constant rate until the water level was a few inches above the spa light. Then it dropped very slowly for days until the leak detection company came. There was a slight discoloration - water mark - in the spa which seems to indicate the water stayed level - about halfway up the spa light.

What is the main drain sump? Is that the main drain in the pool? My first leak detection company said they tested that. Right before the first leak detection company came, I kept losing prime. They told me I had a main drain leak and plugged the main drain. When the assistant came to do additional testing, he told me that the plug was loose and that my problem was faulty O rings in the Jandy valve that controls the main drain at the equipment pad. I replaced all the O rings for the Jandy valves that control the skimmers and main drain.

around a return fitting or the light niche aor in the main drain sump.