How much borax to raise PH?

[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

[denanbob]

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

Yes, that helped immensly. Thanks so much for taking the time to post all that. So no Borax at all then? When do you use Borax? LOL. Don't kill me...........I'm sorry for all the questions. I bought a fountain adapter for my aqualuminator today so I'm going to use that (I was going to add some Borax, but maybe I won't). I need to raise the PH before I use more acid to lower the alkalinity again, that I'm understanding. At the pool store, my numbers were 170 ALK and 7.0 PH. I will aerate to raise to 7.2, acid to lower to 7.0, and keep doing that until my ALK is in the target range. Right???

[chem geek]

After you get your TA where you want it (and after you are through with the TA lowering procedure), then if your pH gets too low at some point you can use Borax to raise it. However, unless you use an acidic source of chlorine (e.g. Trichlor) or a non-chlorine shock (e.g. potassium monopersulfate) or add CYA directly, then there shouldn't be anything in your pool making your pH go down.

The natural tendency for pool water is to go up in pH because it's been intentionally over-carbonated (like a tasty beverage!) and the outgassing of the excess carbon dioxide will tend to make the pH rise. Of course, when you stop the aeration, this tendency will be lessened, hopefully to the point where your pH will be stable. A lower TA will help this stability because carbon dioxide outgassing is faster at low pH, high TA, and with more aeration (so conversely, pH is more stable at higher pH, lower TA, and with less aeration).

Eventually, the slow outgassing of carbon dioxide and the small amount of acid you may add over time to maintain pH will result in a slow lowering of TA at which point you can increase it, but with properly adjusted water parameters, that day may never come. Every pool has a sweet spot or balance and after you've got your TA lowered, you'll learn what that is for your pool.

Richard

[tphaggerty]

I just went through something very similar. Opened pool to low PH (6.8 or lower), TA was OK, vinyl pool. I did BOTH, aerated and added borax. Why? My PH was low enough that I was worried that the vinyl liner might wrinkle as the pool warmed. So I started aerating (which did bring the PH up, but somewhat slowly) and added a large box of borax. After a few days, everything was fine.

The borax was an insurance policy, it made me feel better to get the PH up fairly quickly.

[Jeffski]

Sounds right to me. I think you only add Borax when your TA is correct and you need to raise your PH a little to get it correct. Great questions. I am still learning also.

[Ohm_Boy]

I like to think of the acid/aeration cycle as a 'ratchet' type of mechanism for adjusting TA.

You crank the TA down by reducing it and the PH with acid, then you 'reset the crank' by aerating to raise the PH back up leaving the TA where it is.

Repeat as necessary.

...but I tend to be a simple type of guy.