I have read that a good alkalinity reading should be 80-120 in a hot tub but I've seen posts on here where people have said they keep theirs at 40-50. What gives?
Correct alkalinity level
- Thread starter Sjde
- Start date
We definitely recommend that TA should be 50 in a hot tub. There is good info in this article about managing TA and pH in a tub.
How do I use Chlorine in my Spa (or pool)?
How do I use Chlorine in my Spa (or pool)?
I haven't looked at it yet but are you saying only if chlorine is used, because we use bromine.
It is the same procedure whether you use bromine or chlorine. The following link also refers to the article pooldv sent you:
How do I use Bromine in my spa (or pool)?)
How do I use Bromine in my spa (or pool)?)
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The primary reason why TFP recommends the use of lower TA levels is to stabilize pH. If one uses the industry stated levels, 80-100ppm, then you will be adding acid of some kind (muriatic acid or sodium bisulfate) very frequently (daily additions) to keep the pH under 8.0.
The "industry" recommends high TA based on a mistaken belief that low TA promotes metal corrosion; it does not. The primary driver of corrosion is pH, not TA.
The "industry" recommends high TA based on a mistaken belief that low TA promotes metal corrosion; it does not. The primary driver of corrosion is pH, not TA.
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I'm back at my computer so I did the calculation in case you want to check yourself (although you should always use Pool Math yourself and not rely on others to give you numbers...even I have been wrong in my calculations). For a 375 gallon tub, you need 14oz of boric acid by weight. If you use borax, then you need 22oz of borax by weight AND 11 fl. oz. of 31.45% muriatic acid to compensate for the pH rise.
Both methods will raise your borate level from 0 to 50ppm.
Both methods will raise your borate level from 0 to 50ppm.
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Is boric acid better than using Spa Down ? Because Spa Down will also lower alkalinity and mine is already too low /low enough?
- May 23, 2015
- 25,667
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Boric acid doesn't lower alkalinity. It will slightly raise it a few ppm (not much). It acts as an additional pH buffer against high pH. Boric acid is technically a weak acid while borax is a strong base.
Spa Down just sounds like dry acid (sodium bisulfate). Why would you add that?
My problem has been low alkalinity (lower than 80, but now I'm finding out that 40-50 is actually okay) and high pH (8.0, 8.2).
Boric acid was suggested here for lowering pH.
Spa Down is what I had been using for lowering pH.
Boric acid was suggested here for lowering pH.
Spa Down is what I had been using for lowering pH.
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