I bought a house with a pool in AZ when I moved here 1 year ago. The pool was emptied/cleaned/refilled at that time. The water has had near perfect readings until about a month ago when I started seeing black/green staining on the pool walls. It didn't look like Algae spots, but more like a stain that continually grew as time passed. I am still not 100% sure what it is or if there is a way to tell for sure.
Anyway I started attacking it as if it were Algae and that is when the problems started. I used the algae killer from the pool store and started shocking with the Calcium Hypo and scrubbing the stains...There was some decrease it seemed in the staining, but it never went away completely. Then I started noticing that my chemistry readings began to fluctuate. The PH went up and the pull was acidic and I had a 7-1 TC/FC reading (6 CC).
After treating this with Soda Ash to bring PH down I continued to shock to get rid of CC and I accomplished that. The only problem is that now both TC and FC barely register at all. Now my PH has dropped and Alkalinity as well. Also, it looks like because of the shocking that my CH has gone way up. Here are the current readings.
FC - 0
TC - 1
PH - 6.8
ALK - 6
CYA - 50
CH - 1000
Of course I was taking direction from the pool store in everything I did. Now after reading these forums that was probably not a good idea. Besides now having to draing the pool (Something I shouldn't have to do since the water is less then a year old but probably related to the shocking). What is the best course of action going forward? The pool is clear, and besides the staining looks ok.