Pool Mate 25-Pounds Premium Calcium Hardness Increaser for Pools, 100%

In this review the Pool Mate 25-Pounds Calcium Hardness Increaser is evaluated for pool owners who need a reliable, cost-conscious way to raise and maintain calcium hardness. The bottom line: this dry granular calcium chloride product is best for those who test low on calcium and want a straightforward treatment that dissolves quickly and restores hardness to the recommended range without the premium price of specialty brands. It is presented as an easy-to-use, measurable solution for preventing corrosion, surface etching, and staining when used as directed.

Key Features

• 100% Calcium Chloride: Provides a fast-acting source of calcium to raise total hardness without adding other chemicals.
• Rapidly increases hardness: Formulated to dissolve quickly so measured increases in calcium ppm can be achieved in a single treatment.
• Prevents surface damage: Helps prevent corrosion, etching and staining of pool surfaces when calcium is kept in the recommended range.
• Clear dosing guidance: 8 ounces raises calcium hardness about 10 ppm per 5,000 gallons, making it easy to calculate required amounts.
• Wide ideal range coverage: Suitable for vinyl, tile, exposed aggregate, marcite, fiberglass and painted pools with recommended ppm ranges provided.

Who It's For

The product is aimed at residential pool owners, maintenance pros and DIYers who regularly test water chemistry and need to correct low calcium hardness. It is particularly useful for pools where low hardness is causing corrosion or etching, and for those who prefer a granular, concentrated formula that dissolves quickly and is easier on the wallet.

Owners who do not test water regularly or who lack a circulating system to disperse the solution may want a professional service or alternative treatment that offers premixed dosing. This is not a multi-purpose sanitizer or clarifier; it addresses calcium hardness specifically.

Pros & Cons

Pros

• Effective at raising calcium hardness to target ranges when dosed correctly.
• Good value compared with more expensive brands while maintaining quality and rapid dissolution.
• Clear instructions and dosing metrics (8 oz per 5,000 gallons = +10 ppm) aid accurate treatment.

Cons

• Granular material can exhibit some clumpiness in storage, which customers reported as a mixed issue.
• Requires mixing in a bucket and proper circulation, so it is less convenient than liquid treatments for some users.

Specifications

Brand	Pool Mate
Active ingredient	100% calcium chloride
Net weight	25 pounds
Dosing example	8 oz raises 10 ppm per 5,000 gallons
Use form	Dry granular (dissolve in bucket before adding)
Ideal calcium ranges	Vinyl 200-300 ppm; Tile/Exposed Aggregate 200-400 ppm; Fiberglass/Marcite/Painted 250-400 ppm

Our Verdict

Pool Mate's 25-pound calcium hardness increaser is a practical, economical choice for pool owners who monitor chemistry and need to correct low hardness. Its 100% calcium chloride formula dissolves quickly and gives clear dosing guidance, making it effective for preventing surface damage and maintaining recommended ppm ranges. For straightforward hardness adjustments, it delivers good value and predictable results.

Frequently Asked Questions

How much will this raise my pool hardness?
8 ounces of product will raise calcium hardness about 10 ppm in 5,000 gallons of water; scale dosing accordingly for your pool size.

How should I add it to the pool?
Mix up to 2 pounds per 5-gallon bucket of pool water, then slowly pour the solution around the pool perimeter while the circulation system runs.

Which pools is it safe for?
It is appropriate for vinyl, tile, exposed aggregate, marcite, fiberglass and painted pools when used to reach the specified ppm ranges.