I have had this problem before. One time it was because I had phosphates in the pool. Another time I believe I didn't have enough cyanuric acid. But this time the CYA level was not in question at least that is what the data is showing and the phosphate test was negative. I did try to find the test kit in Target but they don't carry it...so I will try Walmart tomorrow.

I just put in 6 gallons of 6% plain bleach and will test in an hour like you suggested. I will leave pool pump on all night and test in the am.