This morning I checked the FC with the extended test kit to determine how much FC I am loosing daily. It is approximately 3 ppm per day. Everything else was in check from TA, CYA, etc. TA is around 100. CYA is around 40-45 and FC is kept between 3-5 daily. CC = 0.
Although approximately 20-30 minutes after filter turned on I checked the PH level and the readings were extremely low (All the way at the bottom). They were at 7.6 a few days ago. I checked again with the same results at least 3 more times from the same water sample and had no success. Each time rinsing the testing kit.
Then I obtained another sample and checked 2 more times. Finally the readings were normal. I placed too many drops from the agent bottle the first time.
Q: What could have possibly gone wrong? The kit was ordered 12 months ago. Water is clean with very little dirt in the pool. Filter on 12 hours per day. Or what are the possible causes of significant PH drop over a day or so.