I have an 18,000 gallon "volleyball" pool - shallow on both ends and 6 ft in the middle. It is a gunite pool with a rock waterfall. No spa. 3 years ago there was a serious drought and I had to repair 4 plumbing leaks. All 4 leaks were in pvc pipe buried underground. I was lucky that those pipes were easy to access. At that time I believe that we found another leak with the main drain. When I turn the valve to suck only from the main drain and not the skimmers I immediately develop air in the hair basket and bubbles blow from one of the jets. The leak detection company recommended just turning the valve to completely suck from the 2 skimmers and not at all from the main drain. When I do this I don't see anymore air.
Recently I have noticed that I'm adding more water than usual to the pool. I don't see any water on the equipment pad and no air, bubbles of loss of prime. Last night with the pool pump off I lost about 1/4 inch of water in about 12 hours. I have noticed that there are two small wet spots on the back of the waterfall in the same areas and one of the plants back there seems to be growing better than the others. I believe it is getting more water. Other sites recommend patching the mortar but that doesn't sit well with me. Doesn't a wet spot on the outside mean that water on the inside isn't where it should be? I don't know how waterfalls are constructed. Is there a main pvc pipe inside that pipes the water up to the top of the waterfall and then expels if to run down the rocks? Or is the entire waterfall on the inside just one big cavern that flood with water?
Secondly, in an effort to stop the loss of water I turned the valve to shut off the waterfall completely but it's not working properly. It used to stop all flow of water to the waterfall but now there is still a small trickle that continues to flow on one side. Does this mean that my valve needs to be replaced?
Help please! Thank you!