I'm looking for some educated input. Background: We just had an inground pool built, finished a little over a month ago. Almost immediately I noticed that there was a leak. We were losing at a rate of 1/2 inch per day. The builder came, pressure tested the pipes, got in the pool, said he found the leak. A plug in the main drain wasn't fitted in properly. But a day later we are still losing water at the same rate, absolutely no change. He came again. Put a sealant around where the skimmer meets the pool and took out the light and sealed things up there. Now we are losing water at 1/4 inch a day. He believes that is likely due to evaporation. My instincts are telling me something else is still wrong. We put a bucket in the pool to rule out evap, and it took a few days but the level of the pool is now lower than that of the bucket.
So now my main question:
I backwashed the other day, it had been about a week since it had been done, first time I did it myself. The water leaving the filter was extremely dirty, it took several minutes, and several runs, for it to run clear. Then I rinsed for several seconds, twice. I realized I forgot to buy DE so I turned off the pump. The next day I turned the pump on and added DE to the skimmer. DE wasnt going though, I remembered I had turned off the skimmers before backwashing because the level had gotten low. So I turn the skimmers back on and the water coming from the skimmer pipes into the pump basket was brown. Like muddy water brown. Then white and cloudy when the DE gets there.
What are the possible explanations for the water in the skimmer pipes to have gotten so filled with dirt?
Also after the pressure test, one of the skimmer baskets and that entire compartment was stained light brown, with a layer of dirt at the bottom of the skimmer area. What is likely going on with all this? I"m concerned I have a cracked skimmer pipe.