Ph keeps rising unless I keep ALK very low

[FernTheBrute]

CYA at 20, chlorine around 4. If I keep my TA above 50, my Ph will inevitably creep up above 8 and require daily acid. I've managed to stabilize it last week at 7.5 for a solid 5 days without touching anything, but my TA is currently at 40. Can this be problematic long temr in any way?

 

[jark87]

I’ve learned to live with rising pH. I keep TA around 60 and that has reduced the frequency that I have to add MA, but I still add about a pint per week. I used to have to add it 2-3 times per week when I kept TA in the 80-100 range.

 

[PoolStored]

CYA at 20, chlorine around 4. If I keep my TA above 50, my Ph will inevitably creep up above 8 and require daily acid. I've managed to stabilize it last week at 7.5 for a solid 5 days without touching anything, but my TA is currently at 40. Can this be problematic long in any way?

Yes, you need to maintain at least a TA of 50. 60 is better to give you some wiggle room
Your TA continues to drop because you are forcing your pH down below 7.8 with already low TA.
With a TA of 40-50, it is unlikely your pH got above 8. pH above 8 will have purple hues. If you don't get to purple hues, no need to change it.
You are trying to chase an ideal that just isn't possible.
I would raise the TA to 60. Then leave your pH alone, and it will rise to 7.8 to 8.0. When you (if you ever) get to purple hues, then lower pH only to 7.8. If you don't get purple hues, your pH is 8.0, which is fine.
With TA of 60-80, your pH will be fairly stable from 7.8 to 8.0, and that is just fine!

 

[FernTheBrute]

Yes, you need to maintain at least a TA of 50. 60 is better to give you some wiggle room
Your TA continues to drop because you are forcing your pH down below 7.8 with already low TA.
With a TA of 40-50, it is unlikely your pH got above 8. pH above 8 will have purple hues. If you don't get to purple hues, no need to change it.
You are trying to chase an ideal that just isn't possible.
I would raise the TA to 60. Then leave your pH alone, and it will rise to 7.8 to 8.0. When you (if you ever) get to purple hues, then lower pH only to 7.8. If you don't get purple hues, your pH is 8.0, which is fine.
With TA of 60-80, your pH will be fairly stable from 7.8 to 8.0, and that is just fine!

60 for some wiggle room.... for what exactly? (pardon my ignorance)

Ph at 7.8 - 8.0 isn't supposed to make chlorine way less effective?

 

[mknauss]

Ph at 7.8 - 8.0 isn't supposed to make chlorine way less effective?

Insignificant effect with CYA in the water.

The low CYA gives your TA a high carbonate component. Raise the CYA to 40 ppm and keep the TA at 60-70.

 

[PoolStored]

60 for some wiggle room.... for what exactly? (pardon my ignorance

TA acts as a buffer, stabilizing pH by neutralizing acids and bases introduced into the pool. Below 50 ppm, this buffering capacity is reduced, making pH sensitive to even small chemical additions or environmental changes/influences, potentially leading to pH excursions (low or high) and those we want to avoid.

Ph at 7.8 - 8.0 isn't supposed to make chlorine way less effective?

It is not WAY less effective, is is a little bit less effective. HOWEVER, if you follow our FC/CYA recommendations, the amount of active chlorine (Hypochlorous Acid) is sufficient to kill algae and pathogens across the normal pH of pool water. While there is a bit less active chlorine at 7.8-8 (even 8.2), the percentage difference is less than .5%, and is still sufficient to kill algae and pathogens.

Follow this and you will have PLENTY chlorine! Link-->FC/CYA Levels

 

[FernTheBrute]

Insignificant effect with CYA in the water.

The low CYA gives your TA a high carbonate component. Raise the CYA to 40 ppm and keep the TA at 60-70.

What's the effect of a high carbonate TA? Could it explain why I can't keep my Ph low as soon as I raise TA a little?

 

[ajw22]

What's the effect of a high carbonate TA? Could it explain why I can't keep my Ph low as soon as I raise TA a little?

pH seeks equilibrium with TA. Read…

PH TA Relationship - Further Reading

www.troublefreepool.com

 

[PoolStored]

What's the effect of a high carbonate TA? Could it explain why I can't keep my Ph low as soon as I raise TA a little?

TA is mostly carbonates. CYA contributes a bit to TA, but if your CYA is low, the majority of your TA is carbonates, hence your TA has a high carbonate component.

TA and pH want to be in equilibrium (see article below @ajw22 posted above). With a TA of 60-80, your pH will be stable in the high 7s. When you drive your pH to the low 7s, you are also reducing TA...if you continue to do this, you will end up where you are...a low TA. That is why we recommend raising your CYA a bit, raising your TA a bit, and maintaining a pH 7.8-8.0, only lower pH when you get purple hues, and then only to 7.8...pH should be fairly stable 7.8 to 8.0...

 

[YippeeSkippy]

Just to be sure here- is your pool plaster and new?

 

[PoolStored]

Just to be sure here- is your pool plaster and new?

AGP, liner.