Question on adding borax/baking soda

mjlinss

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Jun 2, 2017
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Columbia, MO
After doing a full battery of tests last night I realized both my PH and TA are very low; ph ~6.8/ TA 30. So Pool math says to add about 4 pounds of Borax and 15 pounds of baking soda. My question is when and what order should they be added? Should I start with one, wait a bit, then add the other? This year is the first year I've actually considered PH and TA so am a newbie where it's concerned. Thanks in advance!
 
Borax first. This will raise your pH and also your TA slightly as well. Once you've added, recheck pH and TA. It may be a good idea to less than the full amount right away. It's easy to add more, hard to add less after the fact. Then if your TA still needs to be raised, then you can go to baking soda. As long as your TA is above 50 ppm, I'd see how your pH behaves and don't intentionally raise it any higher than 60 unless you observe erratic pH "bounce" at that TA level.
 
First you add Baking Soda to get to 60-70ish. You don't have to be exact. Round up to the most convenient amount. Let that circulate an hour or so and brush any clumps to get it dissolved. Then retest pH and TA. With really low TA, pH swings can be really violent, where going over a tiny amount can shift the pH a lot. The alkalinity acts as a sort of cushion. If the TA shows above 60, then adjust the pH according to poolmath. You'll see how the amount of Borax needed will change a lot depending on the TA number.

Next question is, how did it get so low? Just opening and a lot of rain and snowmelt? Overdose of acid? A steady diet of highly acidic trichlor pucks?
 
Interesting... Richard's advice seems contradictory, but I think is also another valid approach. The low TA may cause pH to be erratic, even if that 4 pounds of borax adds ~9 ppm to your TA while changing the pH.

Updated:

To clarify, the experts here agree that when pH is low and TA is bottomed out at 0, the only proper response is to add baking soda to raise TA first to a reasonable level, then address the pH as needed with borax.

In this situation, since TA is not quite bottomed out, both approaches are acceptable. I would suggest, contrary to my original recommendation, that you bump the TA up first to 60 ppm. This may or may not also fix your pH issue, depending on the buffering capacity of your water. If pH is still low after adding baking soda, then use borax.

It's important to note that you not try to do both at the same time as the pH will be affected by both additions.
 
Thanks both for the replies. I'm going to add baking soda to get TA to 60, let it circulate overnight then go from there in the morning with the borax.
Richard, we went on a lengthy vacation and I didn't have anyone I trusted to test and add bleach as needed so I used pucks while we were gone. Thankfully the CYA level only rose to 40 and FC stayed at 4. This is definitely the cheaper and easier fix than slamming the water to get rid of an algae bloom. I'd love to put a SWG in for times like that, but unfortunately it's not in the budget. If only I'd found this site before purchasing and installing the pool I'd have done things differently.
 
To prevent future pH and TA drop, add 1.14 lb baking soda per pound of tabs and your levels will remain good.

For example, if you're going to put in 8 tabs, add 4 lbs baking soda to the pool.

The bicarb will offset the TA drop. The initial TA increase will begin raising the pH at about the same rate as the tabs are dropping the ph for a net neutral result.

How many tabs were used?

What was your TA before?
 
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