Hello again... Been on the BBB method for 3 years.. this year I have a problem that I've never experienced... 19000 gal pool.. this summer has been extremely HOT... and very little rain.. so every few days Ive had to add well water from our house system... the last week I kept the cover on it because water was clear and all my clorine levels were in check.. in years past I did the same with excellent results not much water evaporates and I don't use much Chlorine.. so took the cover off and what appeared to be brown algae... water crystal clear but on the bottom was what appeared to be algae... so did my test again and the CC was 0 or .5 hard to tell.. looked pretty clear... and last nights over night test showed very little if any lose in chlorine... so i did an alkality test and show 290..ph. at 7.8....I know its a bit high.. a test it don't do that just a few times a year.. I have the chlorine levels at 25ppm shocking to get ride of the algae.... and my CYA is 40... should destroy the algae ....by again after work water clear but a film of what appears to be algae on the bottom.. very visible when scrubbed with a broom... so im off to get some M. Acid.. am I headed in the right direction and if i get my ph and alkalitly in check will my brown Crud on the bottom go away?