Thank you for following up on the ozone generator. I've turned it off and increased the SWCG from 20% to 40% to raise FC. Been running it at 1 to 2 ppm per ozone manual with no problems (crystal clear water) other than frequent acid addition to keep pH down below 8, and CH increasing making it hard to maintain an acceptable SI with pool temp up to 94.
Couple of questions: IntelliChlor manual says "FC 2.0-4.0 Above 4.0 ppm may cause corrosion of metal components"
pH : 7.2 - 7.8, CYA : 50-80 ppm, TA : 80-120 ppm

If wheel can not be relied on, how should I do SI, or should I not bother with it?

I just re-read thread from Jan/Feb - 14386 & 14387 - I think ( number at bottom of page I printed out back then ). I'm going to retest everything. I have not been testing very often for CYA or Borate.