Help! I Added Borax. Now pH stuck way above 8.

[Davekro]

My water was nice and balanced. I screwed it up by making a few rookie mistakes in adding Borax. Oye!

1) I read that Borax stabilizes pH, but I did not know that it pretty much LOCKS it at the level it is when Borax is added.
2) This morning my pH was at .6 so I added .4 oz Dichlor at 11:40am. W/o testing pH first, I then added .8 oz of Baking Soda to raise my TA from 40 to 50. And again w/o testing either pH or TA, I added borax at 12:30pm. PoolMath told me to add 20 oz (by wt.) or 19 oz (by volume) of 20 Mule Team Borax. I always want to verify any weight to volume equivalences, so I used a measuring cup on my scale (tared to 0), then added Borax. When my two cup measurer was at 19 oz of volume, the scale showed only 13 oz by weight. I verified on a second (less accurate kitchen scale). Anyway, I put mixed the 19 oz volume/ 13 oz wt. of Borax into a bucket of spa water, stirred, then poured into spa. 15 mins later I tested for pH and it was very, very bright red. I have no idea how to guess how far above 8 that is, so I just called it 9.o in PoolMath.

Starting at 1:00pm, I started adding a sequence of doses of three doses of 20% Mur. Acid (1 oz, 1.2 oz, 2 oz.). The bright red pH color did not seem to budge. I started to wonder if somehow my only 6 week old 20 MA had lost its strength, even though that defies logic.
At 2:30pm, I opened my brand-new jug of 31.45% MA and added 1.5 oz. pH was still sky high.
AT 3:25pm, I decided to focus back to FC, as I had not checked it after adding the .4 oz of Dichlor at 11:40am. At 3:25pm FC was at 0.8, Oops. I added .4 oz of Dichlor. At 4:05pm I tested FC at 6.6, pH at ≈8.5, TA at 110.

At 4:30pm, back to adding more MA trying to drop pH, I added .8 oz 31.45% MA. 15 mins later, still ≈ 8.5 pH, so I added another 1.5 oz MA 31.45%.
At 5:15pm, FC was at 6.0, pH looked only slightly above 8.0, so I called that 8.1 pH.

I stopped adding repeated doses of MA and came to ask here if I should be doing something different from just continuing to add MA??
If I am to continue adding multiple MA doses, can I start making larger doses per addition? At some point might 'the next dose' of MA drop pH drastically all of a sudden? Or each additional dose drop pH approximately the same amount per addition?

 

[Mdragger88]

1st* Be sure that you’re entering your borate level in
PoolMath as it affects how much acid you need to lower ph. (More borates = more acid to do the same job)
By my calculations that would be 33ppm borates based on what you added.
Then use poolmath to calculate the amount of acid to target a ph in mid 7’s from the highest readable value. If it looks darker than the highest just use the highest value on the comparator as your “current” ph.
Repeat until you have a readable ph.
Aiming for mid 7’s prevents over doing it.
Borax must be offset by acid if your goal is simply adding borates.
What you’re experiencing is the reason we recommend using boric acid to add borates instead of borax.
No, Your ph wont magically dramatically fall unless you add too much acid.
It is working- it’s just higher than a readable value.
Check your ta periodically. You’ve got a little work to do to get that back down but it will come down eventually.
Here’s what you did

Heres what boric acid would’ve done when aiming for 33ppm of borates

Borates in pool - Further Reading

www.google.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.google.com

 

[Davekro]

1st* Be sure that you’re entering your borate level in
PoolMath as it affects how much acid you need to lower ph. (More borates = more acid to do the same job)
By my calculations that would be 33ppm borates based on what you added.
Then use poolmath to calculate the amount of acid to target a ph in mid 7’s from the highest readable value. If it looks darker than the highest just use the highest value on the comparator as your “current” ph.
Repeat until you have a readable ph.
Aiming for mid 7’s prevents over doing it.
Borax must be offset by acid if your goal is simply adding borates.
What you’re experiencing is the reason we recommend using boric acid to add borates instead of borax.
No, Your ph wont magically dramatically fall unless you add too much acid.
It is working- it’s just higher than a readable value.
Check your ta periodically. You’ve got a little work to do to get that back down but it will come down eventually.
Here’s what you did
View attachment 559730
Heres what boric acid would’ve done when aiming for 33ppm of borates
View attachment 559732

Borates in pool - Further Reading

www.google.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.google.com

@Mdragger88 ,
Huge thank you for your detailed reply. Thanks for telling me to enter 33 as my borate 'now' amount. That is about 65% of the 50 target. Since I added 13 oz by weight (*19 oz by volume*), which is 65% of the 20 oz. by wt. that Pool Math initially recommended, I guess the 20 oz by wt. was the correct amount to target to get to 50 ppm Borate. Am I missing something, or is the physical volume of 20 Mule Team Borax just much, much larger than whatever form of powdered Borax that Pool Math considers when it equates 20 oz by weight of 'Borax' equal to 19 oz of 'Borax' by volume? I am assuming that by volume, it means, as measured in something akin to a measuring cup.

Searching Home Depot and Tractor Supply, I see Boric acid in powdered form, mostly in Roach Killer products. I assume I do not want to use a roach killer product as a source of Boric Acid. I'd assume it has additives not desired in a hot tub.
The plain Boric Acid I run across in a brief search is also powdered, and in larger quantities for +/- $100.
What are economical sources for Boric Acid in a size appropriate for hot tub use, as opposed to a 1o year supply. ;o) Where do you get Boric acid and is it liquid or powdered?

I believe I am complete with my Dichlor additions and the chlorination dose I add after I soak tonight before calling it a night will be (CDS brand) Liquid Pool Chlorine (10%). This gal. of pool chlorine was Mfg'd Nov, 15, 2023. I read that 10% chlorine 's half-life is 357 days. This being ≈ 5 months old, I figure it has degraded to ≈ 8% as of now. I assume, the estimated current degraded chlorine % should be used in Pool Math, as opposed the 10% shown on the bottle, which was valid the day it was mfg'd, correct?

After a 30 min, soak, I added the first dose of 8% chlorine. 2.6 oz. I'll check FC, TA, and pH in the morning.

 

[Mdragger88]

You can get pure granular boric acid in smaller amounts for around 15-20$ for 2# check duda diesel.com &
Also on amazon.
Should last you for a few fills.

Measure dry things by weight & liquid things by volume.
The poolmath app is only showing me weight suggestions for borax not volume suggestions as you’re describing.

You want granular not powder if you can - powder is harder to dissolve (it just wants to float) this isn’t a huge deal with the small amounts needed for a hot tub but 50# in a pool is another story.
Btw- 30 ppm is just as effective as 50 ppm for the benefits so juat call it good for this fill & get some boric acid for the next fill.
Don’t use roach killer- it has unknown amounts of fillers & is generally powdered also its sometimes blue!

For the fc Test your tub 5-10 minutes after adding your somewhat degraded bleach before using the tub to see how your results compare to poolmath & adjust your percentage setting from there.

 

[Davekro]

Mdragger88,
Thanks for the additional info. OK, I'll stick with my 33 ppm of borates for this fill.
I will be out of town for ≈ 5 days. I am thinking, before I leave, I'll shock the tub to say 15 ppm FC with bleach, then turn the temp. setting all the way down (59ºF). The filtration is set to run 1.5 hours in the morning and the same again at night. The concentrated (chamber mixed) ozone, in the Bullfrog EOS ozone system, is only disbursed when filtration is running. Maybe those concentrated 3 hr/ day ozone treatments will mitigate the FC drop somewhat, with no bather loads. As the tub drops from 102º on day one and more over the following days, I'm hoping the FC will not go below 1-2 ppm. Is it OK to shock the tub even higher than 15 ppm before leaving? I guess the cover will get a strong chlorine cloud. Not sure if that situation, maybe 5-7 days, once per month, will add much degradation to the underside of the cover. My wife will be home, but not using the tub. I may call her and ask if she'll test the FC after a few days.

 

[Mdragger88]

I don’t have ozone to contend with but on my last vacation (6days) my swcg was dead so I did just as you described- raise fc to slam (12ppm for me), turn down temp, & I returned to target fc levels. No problem. It was hot outside so my tub never got below mid 90’s.
If you travel alot you may consider adding a swcg to feed your spa fc during standby times.

 

[Davekro]

Mdragger88,
I am close enough to the hotter central valley in northern Calif. than the SF Bay Area in general. In the summer temps are low 90's to low 100's. Right now, we have been in the mid 70's, but cooling over the weekend. It will be interesting to learn what temps. my tub drops to in no heat periods. I'd guess tub water temps would remain at least slightly above the average daytime temps, especially in the 90+ degree summer. Hey, less kW's used in summer to maintain the 103º temps. In Barstow (115º +), they probably don't need heat, but ICE to maintain a 103º spa water temp... I'm not sure if I lived in a super hot climate, how much I'd want to relax in a "HOT" tub. LOL

I just bought from Amazon, Boric Acid Granular Powder 5 Lb. $21.95. It does not degrade over time, so I'm good to go for the next ≈ 6 refills, so 1.5 to 2 years. Thanks for the tip.

 

[Mdragger88]

In the heat of the summer my tub can get to 108 & throw an overheat code if I forget to set the temp lower in advance.
Its on the covered patio but gets some pretty good mid day sun & parts of the brown cover heats up so hot you can’t touch it sometimes. I usually use it as a place to dry stuff like tennis shoes or vac filters quickly.

 

[Davekro]

In the heat of the summer my tub can get to 108 & throw an overheat code if I forget to set the temp lower in advance.
Its on the covered patio but gets some pretty good mid day sun & parts of the brown cover heats up so hot you can’t touch it sometimes. I usually use it as a place to dry stuff like tennis shoes or vac filters quickly.

I just noticed that member's locations are shown in the data on the left. I see you are a bit south of Memphis. I was curious if you got extreme high temps in summer. I see Memphis has about the same Highs in the summer months (91ºF) as where I live in Northern CA. I don't know how accurate this weather site is, but Memphis' mid-summer overnight low is shown as 74ºF, while for Discovery Bay, Ca it shows a 60º overnight low. So you don't get to cool down overnight much. Ouch.

But I will keep an eye on if my tub creeps up in temp in the mid-summer. I guess we could raise on end of the cover an inch or so to let unwanted extra heat out, especially at night. I wonder if people whose tubs rise above their desired/ max temp. find an ice house and get the largest block of ice they can find and plop it i there. LOL

 

[Mdragger88]

We have some weeks where its a high of 98- 101 for days in a row. In the summer I turn the tub temp down to 99 or so.

 

[Davekro]

Our hot spells used to be the same high 90s to low 100's, but last summer we had a week well over 100 with a few days of 110º. Nice if that was an anomaly, not a trend.