Early 2011 I realized that my in-ground pool had a low pH, down in the four range. It was installed around the late 1980's. I started adding soda ash to bring it up. It has taken since then over 60 lbs and still is only in the mid 6's, falling again after additions. Since then I have had purple coloration, the forum suggests this to be manganese, which clears with time. But two things bug me badly. First is that for a year I have battled algae and to the point of failingly in the summer. Never a problem to me in the past. Chlorine is the base plus some shocks and quaternary ammonium algecides. And now the cement lining is “dissolving”. I did replace recently about one third of the water, but no noticeable improvement.
Were my two problems due to an attempt at pH adjustments?
And is my only recourse to drain the pool and have the cement replaced by a pool company?
Any comments appreciated.