Have had our pool for 7 years - no problems till this week. The pool is under lanai (no debris) and is very clear - have been using EZ Pool and has an ozonator (sp); with 2 chlorine tabs set at 1 on gauge. The alkalinity did go low for extended period. Put alkalinity up in - also put in shock bag (had not used before).
Had water tested - said metal (copper) might be problem - told to put quart of Metal Clear on steps and lounge ledge and brush well. No change. Next step we will clean filters and told to add 5 more lbs of shock. This seems strange to me because we have never been told to use it before.
Test Results: 18000 gal pool;vinyl, cartridge filter; inground: Free Chlorine - 0.24; Total Chlorine - 2.78; Combined Chlorine 2.54; PH - 7.6;Hardness - 128 ppm; Alkalinity (w/stabilizer correction) 78 ppm; Cyanuric Acid - 45 ppm; Copper - 0.3 ppm; Iron - 0 ppm; Phosphate 0 ppm
After cleaning the filters and adding the shock was told to add 8 more lbs of alkalinity up 4lbs at a time diluted ; and then add 21 lbs Calcium Chloride 7 lbs at a time.
Any thing else I should or should not be doing to get rid of staining.