We just had our 25 yr old Phoenix pool chipped out in preparation for a pebble tec finish. There was some spalling in the old plaster but no staining. This is apparently the first time the pool has been resurfaced. Our pool builder thought the shell looked pretty good, but performed some sort of test and determined we have about 2" of gunnite in the pool. Ideally he would like to see a minimum of 3" and suggests we consider adding another 2" of shotcrete to make it bulletproof. It's a pretty big expense on top of the original bid - 3k for the shotcrete and at least another 3k to deal with the in floor cleaning system.
Thanks so much for any wisdom you care to share.
