Ok I have been haveing this problem going on 2 years now.
Open the pool up and cannot get the fc to read.
vinly 24000 inground southern Mississippi
fc 0
tc 1
ph 7.8
ta 120
ch 250
cya doen't change 0-20
salt acording to aqualogic 3000 ppm
I can shock and shock and shock with Cal Hypo and...