Our pool water is now 7 years old and for the past season we have been having calcium build up issues. Recently when I had the water tested all pool parameters were normal except calcuim which came in at 600 ppm. As a result, in a couple of weeks I'm going to do do a drain and fill. My white plaster pool does have some dirt discoloration. Would a 3:1 dilution of muriatic acid and scrub the pool best the best way to go clean the plaster? Would a bleach wash be a less invasive alternative? If yes, any advice on dilution? Thanks in advance.