Our community pool is approaching 50 yrs old and is concrete with a painted surface. Each yr the board hires a guy to repaint. This painting process involves chiseling out old rotten concrete on the floor of the pool, patching it and repainting with rubber based pool paint. This yr I'm the guy they hired to do this. I'm pretty handy around the house, but I'm a homeowner, not a pool repair technician. My plan is to remove the old rotten concrete, patch with hydraulic cement and repaint the entire pool. Is the correct procedure? I've read about replastering but I don't think this pool has a plaster finish. Thanks for any help.