Pool Calcium Hardness Increaser (TH+) – 10 lb
Raise low calcium hardness in your swimming pool with this calcium chloride-based water balancer.
Maintaining appropriate calcium hardness helps support balanced pool water and reduce the risk of surface etching and equipment corrosion associated with calcium-deficient water.
Designed to correct low calcium hardness, this 10 lb product is not a pool sanitizer or a replacement for chlorine or other disinfectants.
What is Calcium Hardness Increaser used for?
Calcium Hardness Increaser is used to raise the calcium hardness level of swimming pool water.
It helps:
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Increase calcium hardness when levels are too low.
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Support balanced pool water chemistry.
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Reduce risks associated with low-calcium water, including etching of susceptible pool surfaces and corrosion of certain equipment components.
Calcium hardness is a separate water balance parameter from pH and total alkalinity.
When should you use it?
Use Calcium Hardness Increaser when a water test confirms that your pool's calcium hardness is below the appropriate level.
The manufacturer's published reference range is 150–350 ppm. The appropriate target for your pool may vary depending on its surface and equipment.
Measure calcium hardness before treatment rather than adding the product on a fixed schedule.
For broader water testing, explore iopool 6-in-1 Test Strips, which include a hardness measurement alongside other water parameters. Confirm that your test specifically measures calcium hardness before using its result to calculate a calcium adjustment.
Learn more about manual water testing with iopool.
Dosage
Manufacturer's published dosage guidance — to be checked against the actual US product label before publication.
The manufacturer provides the following reference dosage:
| Desired calcium hardness increase | Pool water volume | Product amount |
|---|---|---|
| 10 ppm | 1,000 gallons | 2 oz by weight |
The amount needed depends on your pool's actual water volume, current calcium hardness and desired adjustment.
Avoid overtreating.
Important: If more than 3 lb per 10,000 gallons of pool water is required, divide the treatment into separate applications at least 12 hours apart.
How to use Calcium Hardness Increaser
According to the manufacturer's published directions:
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Test your pool's calcium hardness and determine the required amount.
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Pre-dissolve the product in a pail of cool water, adding 1/2 lb of product to 1 gallon of water.
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With the pool pump running, pour the dissolved mixture into the deep end of the pool.
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Repeat as needed until the correct amount has been added, avoiding overtreatment.
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If the required amount exceeds 3 lb per 10,000 gallons, divide it into separate applications at least 12 hours apart.
Use cool water for pre-dissolving. Dissolving calcium chloride generates significant heat.
Always follow the directions on the actual US product label.
Key product information
| Specification | Details |
|---|---|
| Product type | Pool calcium hardness increaser |
| Function | Raises calcium hardness |
| Main chemical ingredient | Calcium chloride |
| Listed net weight | 10 lb |
| Manufacturer's reference range | 150–350 ppm |
| Application | Pre-dissolve before adding to pool water |
| Sanitizing function | None |
Product documents:
Compatibility
The published application directions cover swimming pool water.
Compatibility with specific pool surfaces, saltwater systems, spas and individual equipment configurations must be confirmed using the actual US product label and relevant equipment instructions.
Calcium Hardness Increaser is a water balancer, not a disinfectant.
For additional water monitoring, discover EcO Start + Connect, iopool's smart pool monitoring system. EcO directly measures pH, ORP and water temperature; calcium hardness requires separate manual testing.
Important precautions
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Follow the complete directions and safety information on the actual US product label.
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Wear suitable protective gloves and eye protection when handling the product.
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Avoid contact with skin and eyes, breathing dust and swallowing the product.
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Use cool water for pre-dissolving because calcium chloride releases heat as it dissolves.
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Store in a tightly closed container in a cool, dry, well-ventilated place, protected from moisture.
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Avoid overtreatment and follow the manufacturer's instructions for splitting larger doses.
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Consult the package label and Safety Data Sheet for complete warnings, first-aid instructions and any swimming re-entry requirements.
Frequently asked questions
What is Calcium Hardness Increaser?
It is a calcium chloride-based pool water balancer used to increase calcium hardness when levels are too low.
How much Calcium Hardness Increaser should I add?
The manufacturer's published reference dosage is 2 oz per 1,000 gallons to increase calcium hardness by 10 ppm. The actual amount depends on your pool volume and required adjustment.
How do I add Calcium Hardness Increaser to my pool?
The manufacturer's directions specify pre-dissolving 1/2 lb in 1 gallon of water, then pouring the mixture into the deep end of the pool while the pump is running.
Can I add the entire treatment in one application?
If more than 3 lb per 10,000 gallons is needed, the manufacturer directs you to split the treatment into applications at least 12 hours apart.
Does the iopool EcO monitor measure calcium hardness?
No. EcO directly measures pH, ORP and water temperature. Calcium hardness must be checked separately using an appropriate manual test.