Adjusting Calcium Hardness Levels: Pool School by PoolPlaza Pool Supplies

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Calcium Hardness:  |  Intro
 Testing  |  Adjusting

Hardness – Adjusting

Adjusting Calcium Hardness Levels

Adjusting the Calcium Hardness is something that should be done carefully.  The Calcium Hardness can be
increased by the addition of Calcium Chloride.  

It is important to dissolve the Calcium Chloride in a bucket of water before adding to the pool.  If you
just pour it into the pool without pre-dissolving, it may form scale on the pool surface.

Chemical Adjustment Chart

To Raise the Calcium Hardness Level

Check the chart to see how much Calcium Chloride is needed to raise the CH level as desired.  

To increase Calcium Hardness using Calcium Chloride

Desired Increase in PPM

Gallonage of pool or spa

1,000

5,000

10,000

20,000

50,000>

100,000

10

2 oz. 10 oz. 1 1/4 lbs. 2 1/2 lbs. 6 1/4 lbs. 12.5 lbs.

20

4 oz. 1 1/4 lbs. 2 1/2 lbs. 5 lbs. 12 1/2 lbs. 25 lbs.

30

6 oz. 1 3/4 lbs. 3 3/4 lbs. 7 1/2 lbs. 18 3/4 lbs. 37.5 lbs.

40

8 oz. 2 1/2 lbs. 5 lbs. 10 lbs. 25 lbs. 50 lbs.

50

10 oz. 3 lbs. 6 1/4 lbs. 12 1/2 lbs. 31 1/4 lbs. 62.5 lbs.
*Note:  Do not add more than 10 lbs per 10,000 gallons of water at one time.  If the pool requires more than this, add
the maximum amount then retest 12 hours later and make further adjustments.  

Adding Calcium Chloride to a Pool

Slurry the Calcium Chloride in a bucket and pour the dissolved solution into the pool.   Brush pool
thoroughly to stir up any undissolved material that may land on the bottom.

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.