- 1). Subtract the calcium test result from 200 parts per million to determine the required addition of calcium. If the calcium test result is in the range of 200 to 400 ppm, calcium chloride doe not need to be added. If the result was 150 ppm, the result is 50 ppm.
- 2). Divide the amount to raise calcium by 10 ppm for the calcium multiplier. If the amount to raise the calcium hardness is 50 ppm, as in the example above, divide by 10 ppm for a result of 5.
- 3). Multiply the calcium multiplier by 1.25 for the number of pounds per 10,000 gallons. If the calcium multiplier is 5, as in the example, the result is 6.25 pounds of calcium chloride per 10,000 gallons of pool water.
- 4). Divide gallons of pool water by 10,000 for the water multiplier. For a pool that contains 25,000 gallons of water, the result is 2.5.
- 5). Multiply the water multiplier by result of number of pounds per 10,000 gallons. For a pool that contains 25,000 gallons of water, multiply 2.5 by the number of pounds required to raise the pool water 50 ppm, or 6.25 for a total of 15.6 pounds of calcium chloride.
- 6). Weigh the plastic container before weighing the container full of calcium chloride. Subtract the weight of the container from the weight of the container full of calcium chloride.
- 7). Broadcast the required amount of calcium chloride into the water around the perimeter of the pool. Calcium chloride generates heat when added to water. Do not pour in one area of the pool. If the pool has a liner and more than five pounds must be added, add one half of the required amount, wait one hour and add the other half.
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