Cyclic Battle with High pH and Low TA

[Jeffnhelen]

My pool is almost 9 months old and now that it’s swim season again I’m fighting to keep my pH low and my TA high. I’ve searched online and it mostly seems to deal with pools that have high pH and TA or low pH and low TA.
My pool seems to like to sit higher in the pH, between 7.5-7.8, and usually 7.7-7.8 when I check it every few days; a week at the most. I only see it go higher than that if we run the sheer and bubblers for a good portion of a swim day. My TA likes to sit in the 60-70 range before it needs correction. This correction tends to come from adding MA to keep the pH in check...trying to bring it down to 7.2 based on what Pool Math tells me. The next day I check my TA and it has dropped by around 10 points. So I add the appropriate amount of baking soda to bring it back up and then the next day my pH is back up to 7.6-7.8. This seems like a never ending cycle to keep the two readings where they should be.
I’m using Transchem 31.45% MA and Arm & Hammer baking soda. I used the Pool Math calculator and it says that my usual 24oz of MA will drop pH to 7.2 and TA 8 points. Using the calculator to reverse the 8 point drop in TA shows to add 21oz of baking soda with no affect on pH. If this is true do I have something else going on that causes my pH to sit high?
Also, I would love to go with acid injection to automate that delivery, but when my pH likes to climb every couple of days I would need to add baking soda almost just as often to keep that reading where it should be. How are you guys with injection systems staying on top of your TA?
I have attached my results from this mornings measurements.

 

[mknauss]

Only lower your pH to 7.6 when it hits 8. Let your TA settle as long as it is 50 ppm or higher.

 

[Richard320]

Stop micromanaging if you want to get off the rollercoaster. If your pool prefers a higher pH, let it have its way. pH goes above 7.8, just target 7.6 and be done with it. If you let the TA drop into the 50-60 range, you may find the pH holds steady. Or at least holds for a few days. TA will likely come up again when you add water to replace evaporation losses. You don't need to accelerate it with baking soda.

 

[Jeffnhelen]

Thanks for the suggestions guys. This is my first pool so I tried to keep the measurements within the TFP recommendations. So taking what you guys said into account, when I know I’m going to run the water features, which is usually every time we use the pool, are there any tips or suggestions to managing the pH in that case?

 

[mknauss]

Test and adjust. Just do not push pH low as all that does is consume TA and the pH will rise quickly.

 

[see_feel]

Your pool is the same as mine in age, size, and features. Having a salt pool the PH will tend to be closer to 8 and your shell is also still curing. I dose mine with MA weekly as it will go to 8 in about 7 days. I take it down to about 7.4 and let it drift back up. I am curious to see next year if it stabilizes after my shell has fully cured. I do not overly concern myself with it so long as my pH is between 7.4 and 7.8. My TA stays around 60.

 

[Jeffnhelen]

Test and adjust. Just do not push pH low as all that does is consume TA and the pH will rise quickly.

Good to know...thanks for the valuable information!

 

[Jeffnhelen]

Your pool is the same as mine in age, size, and features. Having a salt pool the PH will tend to be closer to 8 and your shell is also still curing. I dose mine with MA weekly as it will go to 8 in about 7 days. I take it down to about 7.4 and let it drift back up. I am curious to see next year if it stabilizes after my shell has fully cured. I do not overly concern myself with it so long as my pH is between 7.4 and 7.8. My TA stays around 60.

Thanks for the observations on your pool. Sounds like my problem may be related to trying to correct down to 7.2 in an attempt to prolong the next required dosage...may have been shooting myself in the foot.

 

[see_feel]

Thanks for the observations on your pool. Sounds like my problem may be related to trying to correct down to 7.2 in an attempt to prolong the next required dosage...may have been shooting myself in the foot.

So long as you are over 7.2 and under 8 on pH and between 60 - 80 on TA you'll be fine. It's tempting to want to hit the numbers perfect but that will lead to madness. So long as I am in range I am pleased and know that myself, family and friends will enjoy the water.

 

[gorocket1981]

This post helped me too... I always been in a battle with TA and pH. I have been told in the past that we must always target a pH at 7.2 because it is the way to have the chlorine effective.
No matter how dry acid I put in the pool, I don't know why but I have never been able to get a pH at 7.2. I never see that. But each time I put dry acid, TA drop so it was coming too low of my target of 100-120. Last season I battled each week with this and it cost me a lot in dry acid and Alka+ stuff and frustration.

Knowing that it is safe for people and equipment to have a higher pH than 7.2 and lower TA than 100-120, I will let go a bit on that.