how do you adjust the acidity?

[rach24]

Hi,

I have a question, may be silly but we are fairly new hot tub owners.  When I do the test strip it tests for the acidity level as well as the ph.  I have ph adjusting chemicals but if the acidity level is too low or too high, what do I use to adjust it? I haven't found anything in the store and of course I haven't asked the spa dealer either, thought I'd come here and ask.  Thanks in advance!

[Vinny]

Welcome!

If PH or total alkalinity is too low you can try baking soda - it will raise both. They do sell PH up and alkalinity increaser as seperate items. To lower both get some PH down - it works on both at the same time.

Everybody's water is different, I can just use baking soda and my water's PH and alkalinity comes in good. Some people have to raise one while lower another and that sounds like a nightmare to me.

If you have specific readings and need help, post them and I'm sure the people here will be happy to help!

[Chas]

When I do the test strip it tests for the acidity level as well as the ph.

I don't know of a test strip that tests for "Acidity."  Do you perhaps mean Total Alkalinity? Or "Acid Demand?"

[anne]

Hi,

When I do the test strip it tests for the acidity level as well as the ph.  

I just want to clarify that you mean total alkalinity and pH as the two things measured, right? I personally had a hard time with that, as I initally thought of "alkalinity" as a measurement of amount of base rather than buffering capacity.

pH= relative acidity (amount of free  H+)
Alkalinity= amount of HCO2 or H2CO3 available to bind or release H+ and "buffer" your pH.  

Good luck!

[rach24]

sorry, yes I meant alkalinity... not acidity
Thank you!

The Test strip tests for chlorine, alkalinity, ph, water hardness and bromine but I use chlorine so I don't bother with the bromine part.

Rachel

[Chas]

OK - then the TA and pH generally go up and down together. You can add dry acid to lower them. That would be Sodium Bisulphate, found in products like "Spa Down," or "pH Minus" or similar.

To raise the TA more than pH use baking soda (Sodium Bicarbinate) in such products as "Spa Up."

To raise the pH more use Soium Sesquacarbonate or Soda Ash.

If one is way up and the other is way down, drain the tub and refill.

Do not add more than four ounces at a time, and don't retest until at least four hours after adding stuff.

[TubbinSoon, now we be tubbin]

All replies are about raising the levels but to lower the ph you can use ordinalry white vinegar which is a very mild acetic (sp?) acid. Vinegar and baking soda are really inexpensive compared to the small containers of "Up" and "Down" chemicals.

[Brewman]

Larger, and much less expensive containers of Ph increase and decreaser can be found in the swimming pool section of many big box stores.  
The ingredients are exactly the same as in the smaller bottles.  

If I didn't need a lot of Ph decrease to adjust my new water I'd probably be ok with the smaller quantity, but I use enough to where I won't pay thru the nose when I don't have to.