Our pool could be 20 years old, we understand the current plaster is about 9 - 10 years old. Blue plaster.
Short question is: Can water chemistry cause egg-shell cracking/plaster pop offs.
Here's the scenario:
Two years ago, we had maybe half dozen egg-shell cracks. No real pattern. End of last year, and now this year, we have about 20 egg-shell cracks. Plaster began popping off last year. One spot is now about 6" across where the white (plaster of before) shows through. Nice.
In the deep end (8 1/2 feet deep), there could be a pattern not unlike expansive soil cracking where the bottom of the pool is pushed up by expansive soil pressure pushing up on the bottom of the pool. Pattern being the cracks exist at the wall/floor transition in a ring pattern around the deep end of the pool. Fortunately, the cracks are still egg-shell and the cracks are still closed. Pressure plugs in the pool floor are intact and we aren't losing water.
Water line tile, coping, tile/coping joints, skimmers all look good. Plaster is stained...looks greener than it did when we moved in. Got me a stain test kit...going out to check now. Please don't beat me up too hard (yet). LOL