SWCG pool with High CC

[Airstar]

My SWG pool is holding chlorine at 7.5 for months and is clear and no algae,but my combined chlorine went from .5 to 1.5 in a week? Like I said the pool looks great and csi is always good? Can you help me figure it out?

 

[PoolStored]

Clean your test vial with rubbing alcohol, DRY...then retest.

How old are your reagents?

What is your CYA?

Do you ever add anything other than acid, calcium or salt?

 

[Airstar]

Clean your test vial with rubbing alcohol, DRY...then retest.

How old are your reagents?

What is your CYA?

Do you ever add anything other than acid, calcium or salt?

Reagents are new
Cya is 35
Nothing else added

 

[wireform]

You need to do
Overnight Chlorine Loss Test to verify

 

[Airstar]

3 days ago I set my salt system from 15 to 40% to raise chlorine (slam?) my cc tested at 1 today and chlorine at 20.
Cleaned testing vile with alcohol as recommended and will retest chlorine as recommended tomorrow to see the change.
Also moved my salt system to 50% so the retest overnight will be inaccurate. But at least the cc is dropping? Will post results tomorrow.

Thanks,
Tom