Adding Alkalinity Plus

jonyok

New member
Sep 2, 2018
4
Lake Charles, LA
I have a 25,000 gallon in ground gunnite pool which is four months old and live in Louisiana. My pH tends to run high, which my local pool builder told me is typical of a new plaster pool, and I have been adding muriatic acid (per his recommendation) about every other week when the pH has risen above 8.0. However, my alkalinity has been dropping into the 60s. He recommended adding a total of 18 lbs of Alkalinity Plus and instructed me to add 6 pounds at a time and then add muriatic acid a day or two later to keep the pH down, then wait a few days and repeat this process twice more over a weeks time . Now it’s been a couple of weeks and it seems that I am now back to where I started with the pH at 8.0 and alkalinity in the 60s. I realize that adding alkalinity will cause the pH to rise some but it seems that I’ve gotten nowhere with this. Am I adding it wrong or is it expected for the pH to keep going up in a new plaster pool? Any recommendations on how to add Alkalinity Plus differently? I added it with the pump on high, then noticed some recommendations to turn off the pump for a few hours after adding it...would this make a difference?
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,415
Franklin, NC
pH will continue to rise in a new plaster pool for a year or more. It is to be expected.

I don’t know where the PB wanted your TA to be, but I wouldn’t worry until it got below 50 and then I wouldn t raise it more than about 70-80.

TA buffers the speed of pH rise and the higher the TA the faster pH goes up.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,661
Bedford, TX
Jon,

Welcome to TFP... A great place to find the answers to all of your new pool questions, whether "Charles" owns your "Lake" or not... :shark:

I suspect the reason that your TA is dropping a lot is because you are adding more MA than you really need.. Don't reduce your pH to 7.2... Just reduce it to 7.6 or so which will take less MA. It will should still take about the same amount of time to move back to 8.0..

Thanks,

Jim R.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,415
Franklin, NC
I understood that Alkalinity needs to be in the 80-120 range in order to help bufffer the pH properly and was not aware that TA buffers the SPEED of pH rise, rather than the AMOUNT of pH rise.
TA is safe down to the 50's. Yes, TA buffers the speed of the rise in pH, the higher the TA the faster pH rises.

Be careful with only using solid forms of chlorine as they add extra stuff to the water you may not need or want. The TriChlor tabs you are using are almost half stabilizer/CYA and the "TurboShock" you are using is actually "Calcium Hypochlorite" which adds calcium to the pool.

Your pH will slowly stabilize as the plaster cures, but the chemicals being added with the solid chlorine are there almost forever....

How much Pool School have you read? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
 

jonyok

New member
Sep 2, 2018
4
Lake Charles, LA
Thanks everyone for all of your very helpful replies! Pool School and the Pool Math app are great too. Now my alkalinity has dropped to 35 and Pool Math is recommending adding 17 lbs of baking soda. Any suggestions on how to add the baking soda? I’ve seen recommendations to turn the pump off for a few hours after adding it...is that the best way to do it and why?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,464
Laughlin, NV
Just add baking soda to the deep end. Brush and run your pump to mix it in.

Do not do all of that at once. What TA are you targeting?

Please add a signature. Read Pool School - Read This BEFORE You Post
Information in your signature will show up each time you post and it makes advice more accurate as we know what equipment we are dealing with.