pH – Adjusting: Pool School by PoolPlaza Pool Supplies

Pool
Chemistry> pH Balance:  |  Intro
 |  Testing  |  Adjusting

pH – Adjusting

Adjusting pH levels

Adjusting the pH is something that should be done incrementally.  In other words, it is better to make
slight adjustments when the pH gets a little high or low than to wait for the pH to get way off and try to adjust it all back at once.

If the pH is way off, we recommend making an adjustment and then retesting it after 24 hours and adjusting
again. 

To raise the pH level, you add Soda Ash (Sodium Carbonate).  Soda Ash will also raise the Total
Alkalinity of the pool water and in most cases, this is a good thing.

To lower the pH level, you add Muriatic Acid.  It is important that if you want to lower the pH
without significantly lowering the Total Alkalinity, you need to dilute the acid before pouring it into the pool.

Chemical Adjustment Charts

It is important to use the Acid or Base Demand Procedure to help determine how much chemical you need to add
to the pool water to achieve the desired results.

To Raise the pH Level

Add the pH test solution to the test sample to determine the pH of the water.  Don’t pour the test
sample out yet.  If the pH is too low and needs to be increased, add base demand reagent to your test sample drop by drop until the color changes a 7.4 – 7.6
reading.

Adding Soda Ash to a Pool

Slurry the soda ash in a bucket and pour the dissolved solution into the pool.  Another possible
solution would be to pour the soda ash around the edge of the pool in the deep end.  Don’t pour it all in one place or it will cloud up the water very badly.

To increase pH using Soda Ash

Drops of base demand reagent

Gallonage of pool or spa

1,000

5,000

10,000

20,000

50,000

100,000

1

1 1/2Tsp

1/4 Cup

1/2 Cup

1 Cup

1 1/2 Lbs

3 Lbs

2

1 TBS

1/2 Cup

1 Cup

2 Cups

3 Lbs

6 1/2 Lbs

3

1 1/2 TBS

3/4 Cup

1 1/2 Cups

3 Cups

5 Lbs

9 1/2 Lbs

4

2 TBS

1 Cup

2 Cups

4 Cups

6 1/2 Lbs

13 Lbs

5 

1/4 Cup

1 1/4 Cups

2 1/2 Cups

3 Lbs

8 Lbs

16 Lbs

6*

1/4 Cup

1 1/2 Cups

3 Cups

4 Lbs

9 1/2 Lbs

19 Lbs

7*

1/4 Cup

1 3/4 Cups

3 1/2 Cups

4 1/2 Lbs

11 Lbs

22 1/2 Lbs

8*

1/2 Cup

2 Cups

4 Cups

5 Lbs

13 Lbs

25 1/2 Lbs

9*

1/2 Cup

2 1/4 Cups

4 1/2 Cups

6 Lbs

14 1/2 Lbs

29 Lbs

10*

1/2 Cup

2 1/2 Cups

5 Cups

6 1/2 Lbs

16 Lbs

32 Lbs
*Note:  If the pool or spa requires more than 5 drops of BDR to reach the desired pH level, add the amount indicated for 5
drops BDR and retest the next day.  This will help to keep you from over treating a pool if you make a mistake.

To Lower the pH Level

Add the pH test solution to the test sample to determine the pH of the water.  Don’t pour the test
sample out yet.  If the pH is too high and needs to be decreased, add acid demand reagent to your test sample drop by drop until the color changes a 7.4 – 7.6
reading.

Adding Muriatic Acid to Lower pH Level

Add the Muriatic Acid to 5-10 parts water and pour around the deep end of the pool.  Keep the pool
circulating so that the acid does not drop to the bottom and etch the plaster.  Note that acid is heavier than water.

To Decrease pH using Muriatic Acid

Drops of acid demand reagent

Gallons of water in pool or spa 

1,000

5,000

10,000

20,000

50,000

100,000

1

1 oz.

5 oz.

9 oz.

1 pt

1 qt

3 qts.

2

2 oz.

9 oz.

18 oz.

1 qt

3 qts.

6 qts

3

3 oz.

14 oz.

27 oz.

1 qt

4 qts

9 qts.

4

4 oz.

18 oz.

1 qt.

2 qts.

5 qts

11 qts

5

5 oz.

23 oz.

1 qt.

3 qts.

7 qts

14 qts

6*

5 oz.

27 oz.

2 qts.

3 qts.

8 qts

17 qts

7*

6 oz.

32 oz.

2 qts.

4 qts.

10 qts

5 GAL

8*

7 oz.

37 oz.

2 qts.

4 qts.

10 qts

6 GAL

9*

8 oz.

41 oz.

3 qts.

5 qts.

13 qts

6.5 GAL

10*

9 oz.

46 oz.

3 qts.

6 qts.

3.5 GAL

7 GAL

*Note:  If the pool or spa requires more than 5 drops of ADR to reach the desired pH level, add the
amount indicated for 5 drops ADR and retest the next day.  This will help to keep you from over treating a pool if you make a mistake.

BEWARE OF THE DANGEROUS NATURE OF THE CHEMICALS YOU ARE HANDLING.  DO NOT MIX ANY
CHEMICALS WITH EACH OTHER.  WATCH OUT FOR FUMES.  SOME CHEMICALS GIVE OFF STRONG FUMES THAT CAN CAUSE SERIOUS PERSONAL INJURY IF INHALED IN SUFFICIENT
QUANTITIES.  MSDS SHEETS ARE AVAILABLE UPON REQUEST.