High acid low pH

[DMS2014]

We went from
7.6, 7.8 went down to 7.0. Chlorine high then low

Husband is wondering why in just 2 days it changed so much

It’s 450 gallons.

 

[frustratedpoolmom]

Is this a spa? if you test pH after adding chlorine it will give you a false high pH reading.

 

[DMS2014]

Hot tub and we were just testing. Hadn’t added anything that day. 2 days before we had

 

[Oly]

We went from
7.6, 7.8 went down to 7.0. Chlorine high then low
Husband is wondering why in just 2 days it changed so much
It’s 450 gallons.

How are you testing, what type of test kit are you using?
If your pH is bouncing around then you need to test the TA total alkalinity of your water and get it into the proper zone of 50-80 ppm.
Free chlorine will drop every day with no use. If you use the spa the FC will drop even faster as it works to keep your water sanitized.
Your job is to keep the Free Chlorine in the zone relative to your CYA, cyanuric acid level.
If you need help understanding water chemistry and your spa read this .........How do I use Chlorine in my Spa (or pool)?

 

[frustratedpoolmom]

Hot tub and we were just testing. Hadn’t added anything that day. 2 days before we had

That's my point, when you tested the chlorine 2 days prior it was high, as was your pH. After 2 days of not adding any chlorine, the pH dropped.

I suspect your pH is actually 7.0... but since you only said "high" and "low" on chlorine and not actual numbers its a guess at this point.