pH of 12?

[Amrie]

Someone in a different group asked advice about a pool that went from "perfect levels" to very high pH in under two weeks. They claim at its worst the pH was 12. Twelve. Like each and every day of Christmas, their true love gave to them... +1 pH.

I'm not a chemist (English major) but my gut reaction is that's impossible unless they filled their pool with draino. They claim they did not, in fact, fill their pool with draino. I'm willing to take their word for that. They also claim they tested the water with a properly calibrated sensor as well as a pro test kit.

Is there any way this could happen, naturally or accidentally, at all, let alone in under two weeks? I thought pool pH would cap out in the low to mid 8s, or at least take years of some weirdly imbalanced process to gradually rise to a level that absurd. Am I mistaken?

(If so, why don't we hear more stories of people getting turned to skeletons from jumping into untested waters? Do they dissolve completely and vanish unnoticed? Omg, is THAT the true origin of mustard algae?)

 

[PoolStored]

Get a recommended test kit. Link-->Test Kits Compared

Post a full set of test results. FC, CC pH, TA, CH, CYA.

We can go from there...

 

[JamesW]

pH: When aqueous solution has a pH less than or equal to 2, or greater than or equal to 12.5, it is considered corrosive.

https://dtsc.ca.gov/corrosive-wastes/

 

[JamesW]

They claim at its worst the pH was 12

Highly doubtful.

Can they explain how the pH got so high?

Maybe with fresh plaster, they might get above 10, but 12 is very unlikely.

What was the TA?

 

[JamesW]

Under GHS, a chemical should be considered as Skin Corrosive Category 1 if it has a pH<=2 or >=11.5 in the absence of other info.

pH Value

Understanding pH Value and Its Regulatory Implications

www.chemsafetypro.com

 

[JamesW]

Skin effects may be indicated by pH extremes such as ≤2 and ≥11.5 especially when associated with significant acid/ alkaline reserve (buffering capacity).

Generally, such substances are expected to produce significant effects on the skin.

In the absence of any other information, a substance is considered corrosive (Skin Category 1) if it has a pH ≤2 or a pH ≥11.5.

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1200AppA

 

[JamesW]

https://www.osha.gov/sites/default/files/publications/OSHA3844.pdf

https://www.schc.org/assets/docs/ghs_info_sheets/Skin%2520Corrosion%2520%2520Irritation%2520(Final%25202018-03).pdf

 

[JamesW]

0.01 molar sodium hydroxide will have a pH of 12.

That is 0.4 grams per liter.

That is 100 lb of sodium hydroxide added to 30,000 gallons of water.

 

[JamesW]

Sodium carbonate solution has a pH of 12 at 106 g/l at 25 °C (77 °F) (1.0 Moles per liter).

0.1M has a pH of 11.5.

26,538 lb for 30,000 gallons.

https://www.sigmaaldrich.com/US/en/sds/sial/s7795

y=100÷(1+10^(10.33 – x)) and y=100-(100÷(1+10^(10.33 – x))), x from 8 to 12.5 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

 

[JamesW]

Sodium carbonate has a pH value of 11.37 for a 1 wt % solution, 11.58 for a 5 wt % solution, and 11.70 for a 10 wt % solution .

At 25 °C, the pH of 1, 5 and 10 wt% sodium carbonate solutions are 11.37, 11.58 and 11.70, respectively.

Sodium Carbonate 0.1 M has a pH of 11.5.

If you added 1,000 lbs of sodium carbonate (pH Up) to 12,000 gallons of water, the pH would only get to 11.37.

The only way to get to a pH of 12 is to add at least 40 lbs of sodium hydroxide to 12,000 gallons of water.

 

[Amrie]

Get a recommended test kit. Link-->Test Kits Compared

Post a full set of test results. FC, CC pH, TA, CH, CYA.

We can go from there...

It's not my pool, thank goodness

 

[Amrie]

Highly doubtful.

Can they explain how the pH got so high?

Maybe with fresh plaster, they might get above 10, but 12 is very unlikely.

What was the TA?

They cannot explain how it got so high. It's an Intex pool, so no plaster. Several people asked about the TA, and the reply every time was that the TA is "spot on." I suggested their meter may not be giving accurate results, and they assured me that it is and that it's not at all unlikely for a pool to hit 12. I couldn't reconcile this with anything I think I know about water chemistry, but I'm new to pool ownership, so I thought I'd get a quick reality check from TFP. Thanks for confirming it's doubtful.

 

[Amrie]

Skin effects may be indicated by pH extremes such as ≤2 and ≥11.5 especially when associated with significant acid/ alkaline reserve (buffering capacity).

Generally, such substances are expected to produce significant effects on the skin.

In the absence of any other information, a substance is considered corrosive (Skin Category 1) if it has a pH ≤2 or a pH ≥11.5.

https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1200AppA

Yes, the whole experience makes me thankful I found TFP. Can't tell you how many folks in the other group responded with "if it's clear, swim!" or "quit wasting time testing, summer is almost over!" Meanwhile I'm imagining kids getting in and Halloween skeletons getting out hahaha!

 

[ajw22]

They cannot explain how it got so high. It's an Intex pool, so no plaster. Several people asked about the TA, and the reply every time was that the TA is "spot on." I suggested their meter may not be giving accurate results, and they assured me that it is and that it's not at all unlikely for a pool to hit 12. I couldn't reconcile this with anything I think I know about water chemistry, but I'm new to pool ownership, so I thought I'd get a quick reality check from TFP. Thanks for confirming it's doubtful.

Ask them to test their tap water for pH and TA with their meter.

If their tap water has pH in the 7s then drain the pH 12 water and refill.

I doubt their pH is 12.

 

[Amrie]

Ask them to test their tap water for pH and TA with their meter.

If their tap water has pH in the 7s then drain the pH 12 water and refill.

I doubt their pH is 12.

I also doubt it. It's just a post in a different pool group, and they aren't interested in my theory that their meter might not be accurate. I don't need to convince them, just wanted a quick reality check for myself!

 

[ajw22]

I am sure they are proud of their 12.

 

[Donldson]

Their pH is not 12.

 

[JamesW]

They also claim they tested the water with a properly calibrated sensor as well as a pro test kit.

Pool test kits cannot measure over 8.5.

Several people asked about the TA, and the reply every time was that the TA is "spot on." I suggested their meter may not be giving accurate results, and they assured me that it is and that it's not at all unlikely for a pool to hit 12.

The TA would be at least 500 with a pH of 12.

There is pretty much no way that the pH is 12.

You might get to 10 in the most extreme cases.

A pH of 12 is 100 times more basic than a pH of 10.

 

[JamesW]

You would need to add 50 lbs of lye to 15,000 gallons to get to a pH of 12.

 

[JamesW]

Alkali. (Also referred to as a base).

A compound that has the ability to neutralize an acid and form a salt.

Alkali also forms a soluble soap with a fatty acid.

Alkalis have pH values between 7 and 14.

They are bitter in a water solution.

Alkalis with pH values between 12 and 14 are considered to be corrosive (caustic) and will cause severe damage to the skin, eyes and mucous membranes.

Common strong alkalis are the substance sodium and mixture potassium hydroxide.

https://www.osha.gov/sites/default/files/publications/OSHA3844.pdf