Ok this is my first time here and I really hope someone can help. I'll provide a ton of background info first. I bought a house last year with a large in-ground pool. The pool is basically a rectangle about 14' wide and 36' long. It is about 3.5' deep in the shallow end and 9.5' in the deep end. The pool had been empty for nearly 2 years before I bought it and the previous owner didn't speak English and was no help. It had a large crack that ran almost the entire length of the pool and up the deep end side wall. I was to told to leak test it before doing any work and has American Leak Detectors come out. They said since the pool was empty they could only check the plumbing which they charged me $650 to do. They said it good. I had a mason cut a V trench in the crack and then fill it in. After that the pool was repainted and I thought I was ready to go.
My pool leaks after each filling always to the same point, the lower edge of the return lines and about 7" below the skimmer. I had American Leak Detection come out again and the guy dye tested some of the return lines and the area around the light, charged me $500 and again said everything was fine. He couldn't finish the job because he said the water was too cloudy as my return lines were spouting DE into the pool.
My main problem is this... if the pool shell itself was leaking wouldn't the water continue to drop? At it's longest it went at least 3-4 months without any change, staying right at the lower level of the return lines. I again filled it and within 5 days it dropped nearly 8 inches. I have an attached spa and it drops at the same rate to the same level.
I have now ripped up all the coping and concrete in the backyard and have most of the piping exposed, no wet dirt. The construction guy said my skimmer was leaking but I think it is just A leak and not THE leak seeing as the water level is now 7" below the skimmer.
If anyone has ideas or suggestions I would REALLY APPRECIATE it. Let me know if more info is needed and thanks for your help.