Yes I bought phosphate remover but not because I wanted to.
It all started after I did the ascorbic acid treatment per pool school, for metal stains in my pool. The treatment went great and all the stains are gone. Then I stared to bring up the chlorine nice and slow along with the pH. That was going great until I noticed that the chlorine level just would not hold, even after three weeks of doing the treatment. Now I am thinking I have algae so I did the overnight FC test and passed the test just fine. I did the test two more times over a couple of nights cause I did not believe the results and both times passed the test. Then I checked the salt level and found it to be at a low 2600ppm when it should be 3400ppm so I added salt. Surly this must have been the problem? No, still not maintaining chlorine. Then I thought it must be a coincidence, but maybe the SWG went bad at the same time I did the treatment so I called the Pentair service place and they came out and checked the cell. They said the SWG was producing chlorine and that it is probably the amount of phosphates in my pool, over 1000ppb, that is the issue.
Now I know that phosphates is probably not the problem, but I am never going to get warranty service if I don't get them down to an acceptable level, below 125ppb, according to Pentair.
The only other things I remember happening around the same time is the I added 2 quarts of polyquat to keep the algae at bay while I dropped the chlorine down to 0 for the ascorbic acid treatment. I added a quart of sequestrant. The reason why the phosphates are so high, probably, is that my kids where adding dish soap to the trampoline which is a few feet from the pool.
What could have possibly caused the cell to all of a sudden not be able to keep up with the chlorine demand?