Yesterday at 4:30 I tested my water:
FC - 9 ppm (just added LC only)
PH - 7.0 ppm
CC -12 ppm
CH - 175ppm
TA - 110
CYA - 50
I had swapped a bunch of water as my CYA was too high.
I have a 600 gallon hot tub that runs 24/7 @ 102F.
I was in the hot tub 3 times (with my sons) over the 24 hour period.
According to pool math adding 2.5 ounces of 12.5% LC should raise me to 5ppm.
I just added that & my FC (after 30 minutes) was about 2.5ppm. I am using the TFP testkit (the big one) for the FC testing.
Any ideas what I am doing wrong?