Hello,
What are you using to test with? You need your own TFTPRO TEST KIT, don't rely on the pool store results. Vets here will ask you to share these test results:
FC:
CC:
PH:
TA:
CH:
CYA:
At 30k gallons your CYA is low which is why your pool is not holding on to chlorine. However don't add...