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How Do I Raise Alkalinity Without Raising pH?

How Do I Raise Alkalinity Without Raising pH?

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  #1  
Old 07-31-06, 10:44 AM
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How Do I Raise Alkalinity Without Raising pH?

We use baking soda to raise the alkalinity (isn't it the exact same ingredient as Alkalinity Increaser you buy at the pool store?)

Anyway, how do I raise the alkalinity, without the baking soda raising the pH as well? Or do I just have that happen, then have to use pH decreaser?

My pH is at 7.8 right now, and the alkalinity is low according to water test done at the pool store.

I have an inground 18 x 36 vinyl lined pool
 
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  #2  
Old 07-31-06, 11:00 AM
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I don't remember that much about pools(been more than ten years since I was taking care of one), but I do remember quite a bit from the chemistry and physics courses I've taken: Alkilinity is a high pH - if you increase the alkilinity, the pH goes up. Inversely, increasing the acidity lowers the pH. Also, baking soda is not an alkilinity increaser, it is a buffer - it tempers the changes in pH seen when adding acids or bases. Chlorine is a basic (alkaline) substance, so the typical pool problem is to offest the high pH caused by chlorination. This is commonly done by adding small amounts of hydrochloric acid.
 
  #3  
Old 07-31-06, 01:55 PM
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Then why is baking soda the same ingredient as listed in alkalinity increasers (sodium bicarbonate)? Just wondering what the difference is.
 
  #4  
Old 07-31-06, 03:32 PM
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If your pool were too acidic for some reason, the sodium bicarb would help temper that back toward neutral pH. I don't believe it could make it alkaline, however.
 
  #5  
Old 07-31-06, 03:54 PM
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normally when you increase TA the Ph will tend to go up.
you had a chem analyis from your pool store , it will have the amounts Sodium Bicarb to add for TA as well as how much ph decreaser to use if any, always check your PH, and sanitizer after 8-10 hrs of circulation anytime you add any chemicals. you may be surprised sometimes things tend to correct themselves, if not then you may need to help it out a lil.
 
  #6  
Old 08-07-06, 06:21 AM
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Use Borax to raise pH without raising ALK. Get it in the laundry aisle by the baking soda.
 
  #7  
Old 08-09-06, 07:10 AM
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Sorry, got it backwards.
Baking soda will raise ALK, and may also raise pH, depending on alk levels.
Borax will raise pH, without raising ALK.
Soda ash or washing soda will raise both.
 
  #8  
Old 01-10-12, 05:06 PM
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I have been having this same problem. Our hot tub cannot maintain a pH around 7.5 and 100 ppm alkalinity. If I get the alkalinity where it needs to be at 80 ppm (100 ppm would be ideal...) the pH goes way above 8.0. Dropping the pH to around 7.6 brings the alkalinity down to 20-40 ppm.

I really don't understand this as our water is very alkaline at 250 ppm and pH ~8.2 out of the tap. We have been using muriatic acid and sodium bicarbonate to make the adjustments but the water just won't balance. If I get the alkalinity up to 80 ppm and let the pH stay at 8 (where it seems to want to) then the water looks really good. If I get the pH to 7.6 (alkalinity is 20-40 ppm) then the water seems somewhat hazy.

Does anybody have any experience with this? Or any advice on how to remedy the situation?

Thanks.
 
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