Chapter 6: Water Treatment Tables:

Volume Calculations

Chemical adjustments are vital to proper sanitation and water balance. Since adjustments are based on the volume of water in the pool or spa, it is important to calculate the volume correctly. The following formulas may be used:

1. Rectangular or square shaped pool
(length x width x average depth x 7.5)

Example 1 (U.S. Customary Units):

length = 40 feet
width = 20 feet
avg. depth = 4.5 feet
volume = (length x width x average depth x 7.5) 40 x 20 x 4.5 x 7.5 = 27,000 gallons

Example 2 (Metric Units):

length = 12m
width = 6m
avg. depth = 1.5m
volume = (length x width x average depth x 1,000) 12 x 6 x 1.5 x 1,000 = 108,000 liters

2. Any circular shaped pool
(diameter 1 x diameter 2 x average depth x 5.9)

Example 3 (U.S. Customary Units):

diameter 1 = 20 feet
diameter 2 = 20 feet
avg. depth = 4 feet
volume = (length x width x avg. depth x 5.9) 20 x 20 x 4 x 5.9 = 9,440 gallons

Example 4 (Metric Units):

diameter 1 = 6m
diameter 2 = 6m
avg. depth = 1m
volume = (length x width x avg. depth x 785) 6 x 6 x 1 x 785 = 28,260 liters

3. Circular Spa
(diameter 1 x diameter 2 x average depth x 5.9)

Example 5 (U.S. Customary Units):

diameter 1 = 4 feet
diameter 2 = 4 feet
avg. depth = 3 feet
volume = (length x width x average depth x 283) 4 x 4 x 3 x 5.9 = 283 gallons

Example 6 (Metric Units):

diameter 1 = 1.5m
diameter 2 = 1.5m
avg. depth = 1m
volume = (length x width x average depth x 785) 1.5 x 1.5 x 1 x 785 = 1,766 liters

Conversion Table:

1 ounce (dry) = 28.35 grams
1 ounce (liquid) = 29.57 milliliters
1 teaspoon (dry) = 5 grams
1 teaspoon (liquid) = 5 milliliters
1 pint = 0.4732 liter
1 gallon = 3.785 liters
1 pound = 453.6 grams
1 foot = 0.3048 meter

Adjusting pH

It is recommended that dry chemicals first be mixed into a generous amount of 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.

A pH range of 7.2 - 7.8 is ideal for pools and spas. Since 7.5 is the midpoint of this range, we have provided the tables below to help in adjusting up or down to this pH. After testing the pH, find the pH in the left hand column and match this with the volume of water in your pool or spa, listed at the top of the table. Since the recommendations are approximate, you may wish to initially add slightly less and wait 4-8 hours to retest the water. Keep in mind that pH adjustments will affect alkalinity.

Lowering pH to 7.5 with Muriatic Acid

Notes:

Treatment recommendations are affected by total alkalinity. At low alkalinity levels less acid may be required and at higher alkalinity levels more acid may be required.

U.S. Customary Units:

Starting from	100 Gallons		1,000 Gallons		5,000 Gallons		10,000 Gallons		20,000 Gallons		50,000 Gallons
pH	—	Tsp	Pt	Oz	Pt	Oz	Pt	Oz	Pt	Oz	Pt	Oz
7.6 - 7.8	—	0.75	0	1.3	0	6.4	0	12.8	1	9.6	4	0
7.8 - 8.0	—	1	0	1.9	0	9.6	1	3.2	2	6.4	6	0
8.0 - 8.4	—	1.5	0	2.6	0	12.8	1	9.6	3	3.2	8	0
>8.4	—	2	0	3.2	1	0	2	0	4	0	10	0

Metric Units:

Starting from	400 Liters		4000 Liters		20000 Liters		40000 Liters		80000 Liters		200000 Liters
pH	liters	mL	liters	mL	liters	mL	liters	mL	liters	mL	liters	mL
7.6 - 7.8	—	4	0	41	0	200	0	400	0	800	2	0
7.8 - 8.0	—	6	0	59	0	300	0	600	1	200	3	0
8.0 - 8.4	—	8	0	81	0	400	0	800	1	600	4	0
>8.4	—	10	0	100	0	500	1	0	2	0	5	0

Lowering pH to 7.5 with Dry Acid (Sodium Bisulfate)

U.S. Customary Units:

Starting from	100 Gallons		1,000 Gallons		5,000 Gallons		10,000 Gallons		20,000 Gallons		50,000 Gallons
pH	—	Tsp	Lb	Oz	Lb	Oz	Lb	Oz	Lb	Oz	Lb	Oz
7.6 - 7.8	—	1	0	1.6	0	8	0	16	1	12	5	0
7.8 - 8.0	—	1.5	0	2.4	0	12	1	4	3	8	8	0
8.0 - 8.4	—	2	0	3.2	0	16	1	12	4	4	10	0
>8.4	—	2.5	0	4	1	0	3	0	5	0	13	0

Metric Units:

Starting from	400 Liters		4000 Liters		20000 Liters		40000 Liters		80000 Liters		200000 Liters
pH	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g
7.6 - 7.8	0	5	0	48	0	240	0	480	0	840	2	400
7.8 - 8.0	0	7	0	72	0	360	0	600	1	980	3	840
8.0 - 8.4	0	10	0	96	0	480	0	840	2	40	4	800
>8.4	0	10	0	120	0	480	1	440	2	400	6	240

Notes:

Treatment recommendations are affected by total alkalinity. At low alkalinity levels less acid may be required and at higher alkalinity levels more acid may be required.

Raising pH to 7.5 with Soda Ash

U.S. Customary Units:

Starting from	100 Gallons		1,000 Gallons		5,000 Gallons		10,000 Gallons		20,000 Gallons		50,000 Gallons
pH	—	Tsp	Lb	Oz	Lb	Oz	Lb	Oz	Lb	Oz	Lb	Oz
7.2 - 7.4	—	0.4	0	0.6	0	3.2	0	6.4	0	12.8	2	0
7.0 - 7.2	—	0.6	0	1	0	4.8	0	9.6	1	3.2	3	0
6.8 - 7.0	—	0.8	0	1.3	0	6.4	0	12.8	1	9.6	4	0
<6.7	—	1	0	1.6	0	8	1	0	2	0	5	0

Metric Units:

Starting from	400 Liters		4000 Liters		20000 Liters		40000 Liters		80000 Liters		200000 Liters
pH	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g
7.2 - 7.4	0	2	0	18	0	96	0	192	0	384	0	960
7.0 - 7.2	0	3	0	30	0	144	0	288	0	576	1	440
6.8 - 7.0	0	4	0	39	0	192	0	384	0	768	1	920
<6.7	0	5	0	48	0	240	0	480	0	960	2	400

Notes:

Treatments in low alkalinity waters require less soda ash while treatments in high alkalinity waters may require more soda ash.

Adjusting Chlorine

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.

Best results are obtained by predissolving granular chlorine products, especially if you have a vinyl pool. Trichlor is erosion fed through skimmers or floating passive feeders. Simply add one Trichlor stick or puck. Do not try to break pucks, since these can burn skin.

Raising Chlorine 1 ppm

U.S. Customary Units:

	100 Gallons	1,000 Gallons	5,000 Gallons	10,000 Gallons	20,000 Gallons	50,000 Gallons
	Tsp	Oz	Oz	Oz	Oz	Oz
Sodhypo*	1	1 oz	7 oz	13 oz	1.5 pt	2 qt
Lithium	1/4	0.4	2	4	8	19
Calhypo	1/10	0.2	1	2	4	10
Dichlor†	1/10	0.2	1	2	5	12
Dichlor‡	1/10	0.2	1	2	4	11
Trichlor	—	0.1	1	1.5	3	7

Metric Units:

	400 Liters	4000 Liters	20000 Liters	40000 Liters	80000 Liters	200000 Liters
	grams	grams	grams	grams	grams	grams
Gas	0.4	5	20	40	80	200
Lithium	1	10	55	115	230	570
Calhypo	1	5	30	60	125	310
Dichlor†	1	5	35	70	145	355
Dichlor‡	1	5	30	65	130	325
Trichlor	0.4	5	20	45	90	220
Sodhypo*	3	35	165	335	665	1665

*This is a liquid and the calculation assumes 1 liq. oz. (10%) = 1 dry oz.
† dihydrate form (56%)
‡ anhydrous form (see product label) (62%)

Adjusting Alkalinity

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 Acid

Notes:

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.

Adjusting Hardness

Precautions

Never add water to chemicals; always add chemicals to water.
Never add calcium chloride to skimmer since it produces heat upon mixing with 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.

In most areas of the country a minimum of 150 ppm and an ideal range of 200-400 ppm of hardness is recommended. The only practical way to lower hardness is to drain some water from the pool or spa and refill with water that is lower in hardness.

Once you determine the hardness concentration, calculate how much you wish to add and find this number in the left-hand column. Match this with the volume of water in the pool or spa, listed at the top of the table. Be careful when mixing calcium chloride with water since this can generate a significant amount of heat. Allow the water to circulate 4-8 hours after the chemical is added and then check the hardness.

Raising Hardness with Calcium Chloride

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	10	1	4	2	7	6	2
20	2.5	—	0	4	1	4	2	7	4	15	12	4
30	3.5	—	0	6	1	13	3	11	7	6	18	7
40	5	—	0	8	2	7	4	15	9	13	24	9
50	6	—	0	10	3	1	6	2	12	4	30	11
60	—	1.2	0	12	3	11	7	6	14	12	36	13
70	—	1.4	0	14	4	5	8	10	17	3	42	16
80	—	1.6	1	0	4	15	9	13	19	10	49	2
90	—	1.8	1	2	5	8	11	1	22	2	55	4
100	—	2	1	4	6	2	12	4	24	9	61	6

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	60	0	290	0	590	1	180	2	940
20	0	10	0	120	0	590	1	180	2	350	5	880
30	0	20	0	180	0	880	1	760	3	530	8	820
40	0	20	0	240	1	180	2	350	4	700	11	600
50	0	30	0	290	1	470	2	940	5	880	14	700
60	0	40	0	350	1	760	3	530	7	60	17	640
70	0	40	0	410	2	60	4	120	8	230	20	580
80	0	50	0	470	2	350	4	700	9	410	23	520
90	0	50	0	530	2	650	5	290	10	590	26	460
100	0	60	0	590	2	940	5	880	11	760	29	400

Notes:

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

Adjusting Cyanuric Acid

It is recommended that dry chemicals first be mixed into a generous amount of water in increments of about two pounds, 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.

Usually a 30 - 50 ppm concentration of cyanuric acid will produce good chlorine stabilization. However, your service professional may have a different recommendation. Usually cyanuric acid is added to a skimmer and travels to the filter where it may take 24-48 hours to completely dissolve. Determine how much cyanuric acid you wish to add and find this number on the left-hand side of the table. Match this with the pool or spa water volume listed at the top of the table. Keep in mind that dichlor and trichlor products will add cyanuric acid as well.

Raising Cyanuric Acid

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.	Lbs.	Oz.	Lbs.	Oz.	Lbs.	Oz.	Lbs.	Oz.	Lbs.	Oz.
10	—	0.75	0	1	0	7	0	13	1	11	4	3
20	—	1.5	0	3	0	13	1	11	3	5	8	6
30	—	2.25	0	4	1	4	2	8	5	0	12	8
40	—	3	0	5	1	11	3	5	6	11	16	11
50	—	3.5	0	7	2	1	4	3	8	6	20	14

Metric Units:

	400 Liters		4000 Liters		20000 Liters		40000 Liters		80000 Liters		200000 Liters
To Raise ppm	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g	Kg	g
10	0	4	0	40	0	200	0	400	0	800	2	0
20	0	8	0	80	0	400	0	800	1	600	4	0
30	0	12	0	120	0	600	1	200	2	400	6	0
40	0	16	0	160	0	800	1	600	3	200	8	0
50	0	20	0	200	1	0	2	0	4	0	10	0

Notes:

Cyanuric Acid may require 24 - 48 hours to completely dissolve.

LaMotte Company

Chapter 6: Water Treatment Tables:

Volume Calculations

1. Rectangular or square shaped pool (length x width x average depth x 7.5)

Example 1 (U.S. Customary Units):

Example 2 (Metric Units):

2. Any circular shaped pool (diameter 1 x diameter 2 x average depth x 5.9)

Example 3 (U.S. Customary Units):

Example 4 (Metric Units):

3. Circular Spa (diameter 1 x diameter 2 x average depth x 5.9)

Example 5 (U.S. Customary Units):

Example 6 (Metric Units):

Conversion Table:

Adjusting pH

Precautions

Lowering pH to 7.5 with Muriatic Acid

Notes:

U.S. Customary Units:

Metric Units:

Lowering pH to 7.5 with Dry Acid (Sodium Bisulfate)

U.S. Customary Units:

Metric Units:

Notes:

Raising pH to 7.5 with Soda Ash

U.S. Customary Units:

Metric Units:

Notes:

Adjusting Chlorine

Precautions

Raising Chlorine 1 ppm

U.S. Customary Units:

Metric Units:

Adjusting Alkalinity

Precautions

Lowering Alkalinity with Dry Acid

U.S. Customary Units:

Metric Units:

Notes:

Lowering Alkalinity with Muriatic Acid

Notes:

U.S. Customary Units:

Metric Units:

Raising Alkalinity with Sodium Bicarbonate

U.S. Customary Units:

Metric Units:

Notes:

Adjusting Hardness

Precautions

Raising Hardness with Calcium Chloride

U.S. Customary Units:

Metric Units:

Notes:

Adjusting Cyanuric Acid

Precautions

Raising Cyanuric Acid

U.S. Customary Units:

Metric Units:

Notes:

LaMotte Company

1. Rectangular or square shaped pool
(length x width x average depth x 7.5)

2. Any circular shaped pool
(diameter 1 x diameter 2 x average depth x 5.9)

3. Circular Spa
(diameter 1 x diameter 2 x average depth x 5.9)