I've just drained the pool and am about to star the next process of cleaning, acid etching and repairing the surface before replaster. What do you use to patch any areas of plaster that get removed? In the concrete industry we patch concrete surfaces with either a high build mortar or a product called FC, or Fairing Coat which is a very fine mortar designed for final finish surfaces. Would these work? I would have thought in a pool, you would want something with an adhesive additive? Like acrylic render? Or cement based tile adhesive? Or is it as simple as a sand/cement blend?
The surface seems pretty good but I honestly haven't been over it in detail yet. I've found a couple of places that are a bit drummy, but I know there will be more and there will be places like around the jets and new tiles where I will need repairs.