Temperature during day: ~75 F
FC Test: Before doing my first TFT-100 test, took pool water sample to Pinch-A-Penny, which said my FC was 4.5 ppm, which was too low for CYA of 80 (two consecutive weeks of testing pool sample at store said CYA level was 80). I used pool calculator and it seems I needed about 1 gallon of liquid chlorine to get about 9 ppm FC, which I added to pool. The TFT-100 test results shown above was taken 24 hours after pouring 1 gallon of liquid chlorine into pool.
CYA test: I have to admit I have very low confidence in this test, because I was expecting a value somewhere between 60 to 80 based on Pinch-A-Penny results of our pool sample. I'm not sure if I'm doing this test correctly, but 40 was for sure when the black dot completely disappears without any traces.
According to pool calculator, CSI level is 0.12, which I think is too high, correct? What can I do to bring this CSI level down if it is a significant concern?
I am surprised the FC level is this high. Obviously either Pinch-a-Penny results was way off, or I miscalculated the amount of liquid chlorine I should be putting in pool to take it from 4.5 ppm to 9 ppm.
Any other comments about the test results?