How much borax to raise PH?

[denanbob]

You have a problem and it needs to be fixed quickly. Your pH was at 6.8 and you added acid. That means that it is now well below 6.8 because that's as low as your test kit can measure. It may have been below 6.8 before. You should start aerating your pool by whatever means you can, even if you can only point the eyeballs toward the surface. Get some borax in the water as soon as you can. You're probably going to run the store out. My ~20,000 gallon pool takes about a box of borax to move the pH up 0.1.

Acid does not lower alkalinity.

Acid doesn't lower alkalinity? I thought that's what everyone says to use to lower the alkalinity and then aerate to raise the PH??? Holy smokes am I confused now for sure. Anyway, I realize it's possible for the PH to drop below the 6.8 and I wouldn't know it since that's the lowest my test goes, but it is the same color as the 6.8 and it matches exactly, that's why I thought it was 6.8. If it was lighter than the 6.8, then I'd worry it was lower. But I will put Borax in as soon as I get home from work tonight to hopefully quickly raise the PH. I still don't know how much to add though. I guess I'll start with one box, but how long do I wait before I test to see how much it raised it? Does it take 1 hour or 8 hours? Does anyone know? I'm trying to figure out how much to add in what intervals. Thanks much!

[JohnT]

pH and alkalinity are directly connected. You add acid and the alkalinity drops, but the alkalinity will tend to pull the pH back up and the alkalinity goes back where it was. Aeration while the pH is low is what actually removes the alkalinity from the water and raises the pH.

[chem geek]

Ben's Lowering Your Alkalinity procedure step 3 says:

Use small doses of acid to lower your pH to just above the lowest value on your testkit -- or 6.6, whichever is higher. Do NOT lower the pH to whatever the lowest value on your kit is! In many cases, if you try to do so, you'll ACTUALLY end up with a much lower pH, which can damage your pool. Instead, make SURE that your pH is at least a little higher than the lowest pH value your kit shows. Also, do NOT try to lower your pH all at once; for all sorts of reasons, it's important to do it gradually!

I'm not putting this here to make you feel bad, but to make sure others reading this know to follow Ben's procedure exactly so that this problem can be avoided in the future. In short, do not target the lowest pH measurable on the pH test, but target one level higher. Since most test kits measure down to 6.8, that usually means using a pH target of 7.0 for this procedure.

Richard

[denanbob]

Ben's Lowering Your Alkalinity procedure step 3 says:

Use small doses of acid to lower your pH to just above the lowest value on your testkit -- or 6.6, whichever is higher. Do NOT lower the pH to whatever the lowest value on your kit is! In many cases, if you try to do so, you'll ACTUALLY end up with a much lower pH, which can damage your pool. Instead, make SURE that your pH is at least a little higher than the lowest pH value your kit shows. Also, do NOT try to lower your pH all at once; for all sorts of reasons, it's important to do it gradually!

I'm not putting this here to make you feel bad, but to make sure others reading this know to follow Ben's procedure exactly so that this problem can be avoided in the future. In short, do not target the lowest pH measurable on the pH test, but target one level higher. Since most test kits measure down to 6.8, that usually means using a pH target of 7.0 for this procedure.

Richard

Ok, let me change my question then. If my PH is 6.8 and my ALK is 300, what should I do in what order? For now I'm going to add BOROX right away, but I guess I should say what SHOULD have I done? I *thought* after lowering my ALK, I could aerate and add Borox to raise the PH since the temp is too cold to put the kids in it. I will aerate with raising the jets on one side and a fountain on the other end.

[JohnT]

Ok, let me change my question then. If my PH is 6.8 and my ALK is 300, what should I do in what order? For now I'm going to add BOROX right away, but I guess I should say what SHOULD have I done? I *thought* after lowering my ALK, I could aerate and add Borox to raise the PH since the temp is too cold to put the kids in it. I will aerate with raising the jets on one side and a fountain on the other end.

I would have started aerating right away. Wherever your pH was, it had been there a while, so a day or two longer wasn't going to be a big deal. Aerating at a pH of 6.8 will raise pH and lower alkalinity. As soon as your pH gets to 7.2, push it back down to 7.0 (one step above the lowest you can measure) and keep aerating. Stay at this until the alkalinity is where you want it, then let the pH climb back to the 7.4 to 7.6 range and see where you stand with alkalinity and how stable your pH becomes when you stop aerating.

If you have a fountain that goes on the return, that's a great way to go. If you're close to a pool store and can stop and get one that will go on your pool's return, I think it would be worth it.

[thilbert]

I agree with John here.

I had a very similar situation two seasons ago when I took over from the pool service company my then fiance used.

I had a TA of 400 and a pH of 6.8 or lower. I immediately bought a fountain for the return and installed it. Within a matter of hours, my pH had climbed to 7.0 and I was adding a little acid every 5 hours or so. I think it took me just shy of a weekend to bring my TA to 120 and pH to 7.6.

[chem geek]

Just to be technically correct, aerating raises the pH with no change in alkalinity. Adding acid lowers both pH and alkalinity. So the combination of the two ends up lowering alkalinity at a given pH. Carl explained this in this thread.

ACTIVITY .......... pH .... TA ... In your case (assuming 6.8 is the lowest measurement on the pH test kit)
==================

Acid ................. - ........ - ... Add enough acid to bring pH down to 7.0 (you were already below that so you skip this step)

Aeration ........... + ....... 0 ... Aerate until pH rises to 7.2
Acid ................. - ........ - ... Add enough acid to bring pH down from 7.2 to 7.0 (you may continue to aerate while you do this)
---------------------------------
Aeration & Acid .. 0 ....... - ... Continue this combination (cycling of the two above) until TA is at the target you want

then AFTER you have reached your target TA,

Aeration ........... + ....... 0 ... Aerate until the pH rises to your target pH (say, 7.5).

==================
Net of Above ..... 0 ........ -

So as the other posters said, when you are starting out with low pH but also have high TA, the best thing to do is to just aerate as that will raise the pH without raising alkalinity and gets you started in the above procedure that lowers alkalinity. So specifically in your case, assuming that 6.8 was the lowest measurement on your pH kit, you should have started aerating until you saw the pH rise to 7.0 and then keep aerating to let it rise to 7.2 and THEN add acid to bring it back down to 7.0 (after that, you bounce between 7.0 and 7.2 through aeration and acid addition -- all the while your TA drops). You never target the lowest pH measurement (6.8 on your kit) because you can never really know if it's truly at that pH or if it's lower. Hope that helps.

Richard