Adjusting alkalinity

It is recommended that dry chemicals first be mixed into a generous amount of pool water in increments of about two pounds (1 kg), and the predissolved mixture be distributed evenly around the pool unless directed otherwise.

Precautions

  • Never add water to chemicals; always add chemicals to water.
  • Always follow manufacturer’s recommendations and warnings on product labeling.
  • Never mix two chemicals together since their pH might vary and could cause an explosion or fire.

Alkalinity should be 80-120 ppm. Once you determine the alkalinity, calculate how much you wish to raise or lower it and find this number in the left-hand column. Match this with the volume of water in your pool or spa, listed at the top of the table. Add the recommended amount to the water in small increments. Since alkalinity adjustments affect pH, you should test the alkalinity and pH 4-8 hours after the chemicals are added.

 

Lowering Alkalinity with Dry Acid

U.S. Customary Units:

  100 Gallons 1,000 Gallons 5,000 Gallons 10,000 Gallons 20,000 Gallons 50,000 Gallons
ppm Tsp Oz Lb Oz Lb Oz Lb Oz Lb Oz Lb Oz
10 1.8 — 0 3 1 0 2 0 4 0 10 0
20 3.5 — 0 6 2 0 4 0 8 0 20 0
30 — 1.0 0 10 3 0 6 0 12 0 30 0
40 — 1.3 0 13 4 0 8 0 16 0 40 0
50 — 1.6 1 0 5 0 10 0 20 0 50 0
60 — 2 1 3 6 0 12 0 24 0 60 0
70 — 2.2 1 6 7 0 14 0 28 0 70 0
80 — 2.6 1 10 8 0 16 0 32 0 80 0
90 — 3 1 13 9 0 18 0 36 0 90 0
100 — 3.2 2 0 10 0 20 0 40 0 100 0

 

Metric Units:

  400 Liters 4000 Liters 20000 Liters 40000 Liters 80000 Liters 200000 Liters
ppm Kg g Kg g Kg g Kg g Kg g Kg g
10 0 10 0 100 0 480 0 960 1 920 4 800
20 0 20 0 190 0 960 1 920 3 840 9 610
30 0 30 0 290 1 440 2 880 5 760 14 410
40 0 40 0 380 1 920 3 840 7 690 19 210
50 0 50 0 480 2 400 4 800 9 610 24 20
60 0 60 0 580 2 880 5 760 11 530 28 820
70 0 70 0 670 3 360 6 720 13 450 33 620
80 0 80 0 770 3 840 7 690 15 370 38 430
90 0 90 0 860 4 320 8 650 17 290 43 230
100 0 100 0 960 4 800 9 610 19 210 48 30

 

Notes:Be sure to note chemical precautions. Always follow manufacturer’s recommendations.

 

Lowering Alkalinity with Muriatic AcidNotes:Be sure to note chemical precautions on the previous page. Always follow manufacturer’s recommendations.

U.S. Customary Units:

  100 Gallons 1,000 Gallons 5,000 Gallons 10,000 Gallons 20,000 Gallons 50,000 Gallons
ppm Tsp Oz Pt Oz Pt Oz Pt Oz Pt Oz Pt Oz
10 1.5 — 0 2.5 0 13 1 10 3 4 8 2.5
20 3 — 0 5 1 10 3 4 6 8.5 16 0
30 5 — 0 8 2 7 4 14 9 12.5 24 0
40 — 1 0 10.5 3 4 6 8.5 13 0.5 32 0
50 — 1.3 0 13 4 1 8 2.5 16 0 40 0
60 — 1.6 0 15.5 4 14 9 12.5 19 0 48 0
70 — 1.8 1 2 5 11 11 6.5 22 0 57 0
80 — 2 1 5 6 8.5 13 0.5 26 0 65 0
90 — 2.4 1 7.5 7 5.5 14 10.5 29 0 73 0
100 — 2.7 1 10 8 2.5 16 4.5 32 0 81 0

Metric Units:

Starting from 400 Liters 4000 Liters 20000 Liters 40000 Liters 80000 Liters 200000 Liters
ppm liters mL liters mL liters mL liters mL liters mL liters mL
10 0 10 0 80 0 410 0 810 1 630 4 70
20 0 20 0 160 0 810 1 630 3 260 8 140
30 0 20 0 240 1 220 2 440 4 890 12 220
40 0 30 0 330 1 630 3 260 6 520 16 290
50 0 40 0 410 2 40 4 70 8 140 20 360
60 0 50 0 490 2 440 4 890 9 770 24 430
70 0 60 0 570 2 850 5 700 11 400 28 500
80 0 70 0 650 3 260 6 520 13 30 32 580
90 0 70 0 730 3 660 7 330 14 660 36 650
100 0 80 0 810 4 70 8 140 16 290 40 720

 

  Raising Alkalinity with Sodium Bicarbonate

U.S. Customary Units:

  100 Gallons 1,000 Gallons 5,000 Gallons 10,000 Gallons 20,000 Gallons 50,000 Gallons
To Raise ppm Tsp Oz Lb Oz Lb Oz Lb Oz Lb Oz Lb Oz
10 1 — 0 2 0 11 1 7 2 13 7 1
20 2 — 0 5 1 7 2 13 5 10 14 1
30 4 — 0 7 2 2 4 4 8 7 21 2
40 5 — 0 9 2 13 5 10 11 4 28 2
50 6.5 — 0 11 3 8 7 1 14 1 35 3
60 — 1.4 0 14 4 4 8 7 16 14 42 3
70 — 1.6 0 16 4 15 9 14 19 11 49 4
80 — 1.8 1 2 5 10 11 4 22 8 56 4
90 — 2 1 4 6 5 12 11 25 5 63 5
100 — 2.3 1 7 7 1 14 1 28 2 70 5

 

 

 

 

Metric Units:

  400 Liters 4000 Liters 20000 Liters 40000 Liters 80000 Liters 200000 Liters
ppm Kg g Kg g Kg g Kg g Kg g Kg g
10 0 10 0 70 0 340 0 670 1 340 3 360
20 0 10 0 130 0 670 1 340 2 690 6 720
30 0 20 0 200 1 10 2 20 4 30 10 80
40 0 30 0 270 1 340 2 690 5 380 13 440
50 0 30 0 340 1 680 3 360 6 720 16 800
60 0 40 0 400 2 20 4 30 8 60 20 160
70 0 50 0 470 2 350 4 700 9 410 23 520
80 0 50 0 540 2 690 5 380 10 750 26 880
90 0 60 0 600 3 20 6 50 12 100 30 240
100 0 70 0 670 3 360 6 720 13 440 33 600

 

Notes:Be sure to note chemical precautions. Always follow manufacturer’s recommendations.