I have a curiosity happening with my CYA - it's gone! I've just finished a bout with Mustard Algae and 8 days of shocking at MA+ levels. Before the process I checked and my CYA was 55-60. Prior to that in late July I took a reading of 45-ish. After my bout with MA I checked and it was zero. O.K. My CYA reagent must be bad. Ordered a new 8 oz bottle and a dedicated graduated cylinder and just got done checking. I can fill the test tube to the top and still easily see the dot. What's going on?
Pool has very light use, constant sun all day, water replacement has been < 5 inches since late July. I have the LQ going and additionaly am putting in 96 oz of 6% every other day. Topping off the LQ at about 1 jug per day = daily FC consumption at about 1.5 -2 jugs per day in high 90 degree heat. Keeping my FC at around 13, I want to get to closing without MA rearing its ugly head.
So, can a week's worth of constant high FC (40ish), burn off the CYA level in a pool?