pH Keeps Rising

[Ryano2121]

Numbers this morning from the Taylor kit:

pH 8.0
TA 120
FC 5.4
CH 260 (have really hard water here)
CYA 40

I have been adding 20-40oz of 14.5% muriatic acid per the pool calc recommendation daily in the morning. pH goes down to 7.5 in the evening then goes back up to 8.0 the next morning. Is this normal?

 

[jcowart]

It does not really sound right to jump that fast. Do you have any bubbles coming from the returns. Also is the pump basket completely full. Do you see any bubbles when the pump it running.

 

[Ryano2121]

I have no bubbles in the returns except when the solar comes on of course. The pump basket is full and there are no bubbles.

I just did a 50% water change. Could that have an effect?

 

[ping]

Do you have any type of aeration such as a waterfall, returns turned upward, etc? What are you using for chlorination?

 

[JasonLion]

PH increase (other than chemical additions) comes from fresh plaster, or high TA combined with aeration (negative edge, waterfall, SWG, splashing, bubbler, etc). Your TA is high enough to cause some noticeable PH increase, but unless you have a very high aeration rate yours is faster than we would expect.

 

[Ryano2121]

I have a waterfall but it is off because the cover is on. The pool is 13 or 14 years old. I guess I'll keep adding for a bit and see if it levels out.

Good news is FC is doing great!

 

[Ryano2121]

Stayed at 7.6 overnight.

 

[bkmichael]

I am having the same issue with ph being higher than the day before after adding acid every morning. Sounds like having water fall and bubbles in the return are the cause of the PH rising every day?
I have same size, type pool and readings but pool is only 8 mo. old.

 

[pooladdict]

anything that adds air or aeration to water will increase Ph. Sheesh, 15 kids doing cannon balls can increase Ph.

 

[bkmichael]

But after initial startup and balancing, I didn't have to add acid for weeks, the total alk hovered at 80 to 90, now at 120, cya around 350. I now use liquid chl, not tablets.

 

[chem geek]

Is your TA high in the fill water? Perhaps evaporation and refill has increased it over time. At a higher TA, there will be more pH rise.

Also, if you were using Trichlor tabs after initial startup and balancing, the Trichlor tabs are acidic so effectively were adding acid to the pool to keep the pH from rising as quickly.