Can't keep ph at recommend 7.4

[wingedout]

Hello, I have been using the TFP Test Kit for awhile now. I check my FC and ph everyday and do the whole test on Mondays or Tuesdays. I am not sure if it is common to always have to add Muriatic Acid daily if I average the last 7 days I am adding 37oz daily to bring my ph down to the recommended 7.4 from 8. It always seems to sit around 8

Last full results on Tuesday 5/21/19:
FC 3.5
CC 0
pH 7.8
TA 40
CH 500
CYA 60
Temp 72
CSI -0.26

I know we have to add chlorine daily just don't know if the same for Muriatic Acid. Just seems to be a lot. I did raise my TA from 40 to 85 on Wednesday hoping to stabilize my pH readings. But it didn't still likes to sit at 8 and when it does my app says scaling likely which makes me nervous.

 

[mknauss]

Do not raise your TA if you want to stabilize pH from rising.

Is this new plaster?
I believe the TA of Midland water is pretty high. I know you use RO but not sure if that removes alkalinity.

 

[mknauss]

Lower your pH to 7.6 when it hits 8. No lower.

 

[wingedout]

nope same plaster from install March of 2018. Ok I will only lower to 7.6. I won't mess with the TA anymore I will just test and record. How low should I let the TA get before messing with it again? 60?

 

[mknauss]

As long as TA is 50 or above you are OK.

What is your fill water TA?