How often to test

[sspine]

Thank you for the help last night. I am a newbie converting from Bioguard.
16x36 ig vinyl liner (21,000 g?)
Hayward sand filter
Hayward 2.5 hp pump

I had high TA & CYA so pumped and refilled, added .75 gallon Muratic in 2 doses last night. Current numbers (have added 4 gal Walmart Ultra in past 4 days.

FC 0
TC 0
CC 0
Ph 7.7
TA 175ppm (was 320 before refill and aeration)
CA 250ppm
Cya 58ppm (was 95 before refill and aeration)

I don't know whether to get the clorine going or need to get the TA down more first. We just retired and have been watching this board for sometime now. You are great teachers. I have already learned a lot.

[JohnT]

Your TA is probably not a problem where it is. You need chlorine before things get out of hand. Keep an eye on the pH. The other stuff can be tweaked at your convenience.