Pool Mate Calcium Hardness Increaser for Pools — 16 lb Bag, Fast-Dissolving Granular Formula to Prevent Etching & Staining

Pool Mate 16-Pounds Premium Calcium Hardness Increaser is a fast-dissolving granular calcium chloride formulated to raise and stabilize your pool's calcium hardness to the recommended range.

Maintaining proper calcium hardness prevents etching, staining, and corrosion on pool surfaces and equipment. This 16-pound bag supplies an easy-to-use dose of calcium chloride for routine adjustments—whether you have a vinyl, tile, plaster, fiberglass, or painted pool. Use a reliable test kit first to determine current levels, then follow the dosing guidance to bring your pool into the ideal hardness window.

How do I know when my pool needs calcium hardness added?

Test your pool water with a trusted calcium hardness kit. Levels below recommended ranges indicate the need for this product to protect surfaces and metal fixtures. Low hardness can make water aggressive, which increases wear on finishes and causes etching.

• Vinyl pools: target 200–300 ppm.
• Tile and exposed aggregate: target 200–400 ppm.
• Marcite, fiberglass or painted pools: target 250–400 ppm.
• If your reading is below the target, plan a measured addition of Pool Mate calcium hardness increaser.

What is the correct way to add this product to my pool?

Dissolve the recommended amount in a plastic bucket filled with pool water before adding it to the pool to ensure even distribution and reduce the risk of local staining. Add up to 2 pounds of product per 5-gallon bucket of water. While the pump is running, slowly pour the dissolved solution around the pool perimeter.

• Always pre-dissolve in a plastic bucket—never add dry granules directly to the pool.
• Pour solution slowly around the pool with the circulation system on.
• For a 10,000-gallon pool, do not add more than 10 pounds every two hours.
• Retest after full circulation to confirm desired levels are reached.

How much will this bag treat and how quickly does it work?

The 16-pound bag contains concentrated calcium chloride that dissolves rapidly and begins adjusting hardness as soon as it is circulated. The exact ppm change depends on pool volume; the product description notes that 8 ounces raises calcium hardness by about 10 ppm in 5,000 gallons, which helps you calculate dosing for your pool size.

• 8 ounces ≈ raises 10 ppm per 5,000 gallons.
• Use dosing chart included with the product for precise amounts.
• Smaller incremental additions help avoid overshooting target levels.
• Allow full circulation and retest before making additional adjustments.

Can I use this in all pool types and will it harm equipment?

Pool Mate calcium chloride is suitable for common pool surfaces when used according to directions. Properly adjusted hardness helps protect plaster, tile grout, metal fittings and liners by reducing aggressive water conditions. Avoid over-dosing and follow circulation limits to prevent localized high concentrations.

• Safe for vinyl, tile, plaster, fiberglass, and painted pools when diluted correctly.
• Helps prevent corrosion and etching associated with low hardness.
• Do not add dry granules directly to the pool to avoid surface damage.
• Follow pump run-time and maximum addition rates for your pool volume.

Who is this for: Pool Mate 16-Pounds Premium Calcium Hardness Increaser is meant for pool owners and service professionals who regularly test water chemistry and need a dependable product to raise and stabilize calcium hardness. It's especially useful for older pools showing signs of etching or staining, new plaster jobs that require careful mineral balance, and anyone seeking to protect fixtures and finishes by maintaining recommended hardness levels.