Adjust TA first, right?

[jnorris]

My PH keeps wanting to climb, unless I add acid about once every week or two. Don't have an SWG (wish I did!), and it has rained alot, so can't figure out why. Anyway, in keeping my PH down, I think I have accidently done the "lowering the Alk" procedure, because we run our fountains and bubblers alot too. My Alk was raised up from 80 to 130 about a month ago (PB added baking soda), and it has been creeping down ever since. Now it's 70.

Should I leave PH alone until after I get my TA where I want it? I think I read that somewhere, but can't find it now. If I have a 22,000 gal, vinyl IG pool, how much baking soda should I add? Can I put it in the skimmer? Should I dissolve it first? How long after I add can I do an accurate test, and then add acid to bring PH down?

[cruzmisl]

TA should be adjusted to the appropriate level before ph is adjusted.

Hope this helps,
J.

[Watermom]

I would add a lb. of baking soda at a time. Add it slowly to the skimmer while the pump is running. Don't need to predissolve it. Wait a few hours to let it circulate before retesting. I'd aim for an alk reading of 100. How high is your ph?

[waterbear]

actually, it can take as long as 48 hours for the TA to stabilizer when you adjust it but you should have a good idea in about 8 or so.

[jnorris]

I would add a lb. of baking soda at a time. Add it slowly to the skimmer while the pump is running. Don't need to predissolve it. Wait a few hours to let it circulate before retesting. I'd aim for an alk reading of 100. How high is your ph?

PH is 7.8 to 8.0ish.

I'm going to do as you said. You haven't steered me wrong so far!

[cruzmisl]

You should end up putting about 8lbs of baking soda in (if your pool size and TA readings are correct)

Hope that helps.
Joe

[Watermom]

That may very well be true, but I have found with baking soda, it doesn't always take as much as the bleach calc suggests, so I tend to add slowly rather than overshoot the target. Especially since she is already close to the desired range already.

[PoolDoc]

TA should be adjusted to the appropriate level before ph is adjusted.

WRONG!

PH should be adjusted first. The reason is that your alkalinity will change, if you adjust your pH, and what was a problem, may not be one, once you fix the pH.

The idea that alkalinity should be adjusted first is widespread in the pool industry. There's even a trademarked slogan, "Alkalinity First!"

Can you guess whose slogan it is?

Hint: The are the largest manufacturer and distributor of sodium bicarbonate, both for industrially, and for retail sales. Hint #2: As I just discovered, they even have a BRAND of sodium bicarbonate called "Alkalinity First"

Can't guess? It's Church & Dwight, owner of the "Arm & Hammer" brand.

But, even if you couldn't guess whose slogan it was, now that you know, I'm pretty sure you can figure out why it's their slogan. I'm SURE it has nothing to do with selling you more baking soda than you need!

Ben
PoolDoc

[cruzmisl]

See shows what I know. It was just my 2 cents worth of info which is precisely how much it's worth

[jnorris]

WRONG!

PH should be adjusted first. The reason is that your alkalinity will change, if you adjust your pH, and what was a problem, may not be one, once you fix the pH.

Ben
PoolDoc

OK, so If I want my PH to be 7.4 to 7.6, and my TA between 100 and 120, I should add acid first to get my PH down, and then add baking soda to bring my TA up? Should I wait a certain time in between?