Question on pH stabilizing

[yeomanflood]

Hello. Thanks to everyone that participates in this forum!!

Recent test results:

FC 4
CC 0
pH 8.1
TA 100
CH 300
CYA 40

I use liquid chlorine (10%) & MA (31.45%).
The water in my town is very alkaline - so after refilling it in the summer due to the water being old (high CYA, CH, etc.) and learning about water balance here - I slowly worked my TA down to 100. I was hoping my pH would stabilize around 7.8, but instead it seems to always go to 8.1 - so then I add a little acid, the TA goes down a little (but pretty slowly seems like).

Am I destined to just have to continue to add acid to reduce the pH and eventually start to add baking soda to raise the TA?
Is it OK if my pool is stabilizing at pH of 8.1 - then I can just choose to lower it for swimming (all the while trying to keep my TA at around 80)??

Thanks in advance.

 

[duraleigh]

Is it OK if my pool is stabilizing at pH of 8.1

Not really. Keep your pH in the 7's........that's the advice suggested in Pool School.

Maintaining your pool water within Pool School's guidelines will give you the results you want. However much acid it takes to keep your pH in the 7's is just part of the cost of doing business......much like adding chlorine, CYA or any of the other things necessary.

Make pH your primary target (aside from chlorine :-D ) and let the TA fall where it likes as long as it stays within reason.

 

[Richard320]

The water in my town is very alkaline - so after refilling it in the summer due to the water being old (high CYA, CH, etc.) and learning about water balance here - I slowly worked my TA down to 100. I was hoping my pH would stabilize around 7.8, but instead it seems to always go to 8.1 - so then I add a little acid, the TA goes down a little (but pretty slowly seems like).

Am I destined to just have to continue to add acid to reduce the pH and eventually start to add baking soda to raise the TA?
Is it OK if my pool is stabilizing at pH of 8.1 - then I can just choose to lower it for swimming (all the while trying to keep my TA at around 80)??

Thanks in advance.

What you're describing is perfectly normal. If you plug your numbers into pool calculator then go way down to the bottom where it says "Effects of Adding Chemicals" you'll see that adding, say, 28 oz of acid will lower pH by .37 but TA will only drop 6.1 ppm. So pH is affected more than TA. pH will climb again, and you keep repeating it. But you'll notice as the TA goes down lower and lower that the speed at which the pH rises slows down. And that the amount of acid to keep pH stable goes down too. Eventually you'll hit the sweet spot - and you're getting close, now - where the acid demand will drop to only needing a cup or so once or twice a week.

I doubt you'll ever need to add baking soda. Just refilling the splashout and evaporation with the alkaline tap water will keep it up.

 

[yeomanflood]

Thanks, guys. I will follow your advice and do that and let you know how it goes!

 

[UnderWaterVanya]

My pH rose until my TA reached about 70-75.

Sent via Tapatalk...

 

[yeomanflood]

Thanks for sharing.