How to Lower pH and raise TA

[jtemplin3]

Greetings,

I am in my sixth year of pool operation and am struggling with how to approach balancing my water. I need to add about .5 gal MA each week to keep the pH from going above 7.8. My understanding is that the acid will continue reduce the TA (or at least hold it lower than desired). Is that correct??

	current	my target
pH	7.8 (H)	7.5
FC	3	3 - 5
CC	.25
TA	50 (L)	80
CH	250	< 400
CYA	30	40

I have observed that TA recommendations vary (with respect to the lower limit) quite a bit depending on the info source
TA recommendations from various sources
70 - 90+
80 - 120
80 - 120
60 - 120
100 - 120
80 - 120

Pool was completely re-filled in Jun by local twp from hydrant. Fill was necessary because of a bad hydrostatic valve.

Prior years' TA was between 90-110.

Thanks in advance

 

[Richard320]

Acid lowers both pH and TA.

Higher TA means faster pH rise.

50 is pretty much the lowest you want TA to go, but 80 is higher than you absolutely need.

If you lower pH, you'll lower TA, too, so you'd need to add some baking soda, which will then start pushing pH up again, which puts you in a vicious cycle. How long will the pH sit at 7.8? You might already be at the sweet spot where things are in equilibrium and it won't raise to 8.0 for weeks. If you start micromanaging, you'll constantly be fiddling with the water.

When you do have to add baking soda, only target 60.

And as an aside, your acid consumption doesn't seem outrageous, given the size of your pool.

 

[pooldv]

Here is the official recommendation, Pool School - Recommended Levels

TA does not require a hard and fast number. And there is little need to "chase" a number like 80. The only real rule with TA is that you don't want to let it get too low. If too low then pH can become erratic or even crash to 4.0 or less. So, too low is typically below 50. Some pools can be as low as 40.

There is also no reason to keep your pH at 7.5. 7.8 is fine and in range.

In many pools, managing your pH to 7.8 will reach an equilibrium on TA on its own of around 50-60. Some folks even reach a point where acid is no longer needed and pH remains stable at 7.8.

When your pH reaches 8.0-8.2, depending on which test comparator you use then lower it to 7.8 leave TA alone and see how that works for you.

 

[ajw22]

To say what Richard said in a different way:

Target 7.8 as your PH and look to keep it between 7.6 and 8. Add MA when it hits 8 to take it down around 7.8.

Not lowering PH below 7.6 will impact your TA less.