pH readings don't make sense

[dtrebus]

Hi all,
Last 3 days in August, my pH readings were 8 (TA 100). I added muriatic acid to bring pH to 7.2, and TA went to 90. pH was consistently 7.4 for 5 days, then was at 7.8 and 8. I added more muriatic
acid and TA went to 80 (which was where it was almost all of last season).
The last 6 days, my pH was: 7.4 7.6 7 7.8 7.2 7.8
My FC has averaged 5 (3 low and 6 as high). My CYA is 40.

Why the variations in pH? Just seems like I'm having a harder time with this and keeping FC in ideal range as compared to last year.
Any thoughts? Thank you

 

[cowboycasey]

How long have you had your PH red R-0014 ?

Your PH should not be swinging like that and it is either a testing error or old reagent... PH will not go down from7.6 to 7 without MA

 

[dtrebus]

That's what I was thinking. My reagent says expires 6/21 so ordered new one and will see what the outcome is.
Nice car BTW ;-)