Calcium Hardness Increaser 4kg | Calcium Chloride Pool & Spa
Soft water silently destroying your spa or pool? Calcium Hardness Increaser (Calcium Chloride) is the essential treatment that protects your pool shell, heater, pump, and fittings from the corrosive effects of low-calcium water - while eliminating foaming and etching that soft water causes.
Water with low calcium hardness is aggressive - it actively seeks calcium by leaching it from your pool surfaces, grout, and equipment. The result is pitting, etching, foaming, and expensive equipment damage. A correct calcium hardness level of 200-400 ppm for pools and 150-250 ppm for spas is your first line of defence.
Product Specifications
| Active Ingredient | Calcium Chloride |
| Size | 4kg resealable pail |
| Suitable For | Swimming pools, spa pools, plunge pools, and hot tubs |
| Pool Dosage | 300g per 20,000L raises calcium hardness by approx. 10 ppm |
| Spa Dosage | 15g per 1,000L raises calcium hardness by approx. 10 ppm |
| Target Range (Pools) | 200-400 ppm (varies by surface type) |
| Target Range (Spas) | 150-250 ppm |
Why Calcium Hardness Matters
- Too low - water becomes corrosive, etches surfaces, causes foaming, damages heaters and pumps
- Too high - water turns cloudy, scale deposits form on surfaces and fittings
- Correct calcium hardness = protected equipment, clear water, and longer pool life
- Ideal range for pools: 200-400 ppm | Ideal range for spas: 150-250 ppm
Key Features
- Active Ingredient: Calcium Chloride. The industry standard for raising calcium hardness quickly and evenly.
- Fast-Dissolving. Raises calcium hardness quickly for even distribution throughout the water.
- Dual-Purpose. Suitable for swimming pools, spa pools, plunge pools, and hot tubs.
- Prevents Corrosion. Protects pool shell, heater elements, pumps, and fittings from soft water damage.
- Reduces Foaming. Eliminates foaming caused by soft, low-calcium water.
- 4kg Resealable Pail. Moisture-resistant storage for long shelf life.
Dosing Guide
Spa Pools (per 1,000L):
- Add 15g per 1,000L to raise calcium hardness by 10 ppm
- Example: 150g raises calcium by 100 ppm in a 1,000L spa
- Pre-dissolve in a bucket of water before adding - solution will heat up, this is normal
- Run jets while dosing for even distribution
- Retest after 30 minutes before re-dosing
Swimming Pools (per 20,000L):
- Add 300g per 20,000L to raise calcium hardness by 10 ppm
- Example: 1.5kg raises calcium by 50 ppm in a 20,000L pool
- Pre-dissolve in a bucket of water before adding to pool
- Add near a return jet with pump running
- Allow 6 hours of circulation, then retest before adding more
Important: Always pre-dissolve Calcium Chloride in a bucket of water before adding - never add directly as it can cause localised cloudiness. The solution will get warm - this is a normal exothermic reaction. Always add chemical to water, not water to chemical.
Available Sizes
- 1kg Pail - ideal for spas or small top-up doses.
- 4kg Pail (this product) - most popular for regular pool and spa maintenance.
- 10kg Pail - best value for large pools or frequent use.
Safety and Storage
- Store in a cool, dry place away from direct sunlight and moisture
- Keep away from children and pets
- Do not mix with other pool chemicals
- Pre-dissolving causes heat - use a plastic bucket and handle with care
- Avoid inhaling dust - use in a well-ventilated area
- Wash hands thoroughly after handling
Recommended Accessories
- 5-in-1 Test Strips - test calcium hardness, pH, chlorine, and alkalinity before and after dosing.
- Alkalinity Increaser 4kg - stabilise Total Alkalinity alongside calcium for fully balanced water.
- pH Increaser (Soda Ash) 4kg - adjust pH to the ideal 7.2-7.6 range after balancing calcium.
- Crystalline Chlorine 4kg - sanitise at the correct chemistry for maximum effectiveness.
- Spa Pool Starter Kit - includes Calcium Increaser plus everything needed for a fresh fill.
Frequently Asked Questions
Q: Why does my spa foam so much?
A: Foaming is one of the most common signs of low calcium hardness. Raise calcium to 150-250 ppm and the foaming will reduce significantly. Also check for body oils and detergent residue from swimwear.
Q: How quickly does Calcium Hardness Increaser work?
A: Calcium dissolves and disperses within a few hours. Allow 6 hours of full circulation before retesting.
Q: Why does the solution get hot when I pre-dissolve it?
A: Calcium Chloride is exothermic - it releases heat when dissolved in water. This is completely normal. Always use a plastic bucket and add the chemical to water, not water to the chemical.
Q: Can I add too much calcium?
A: Yes - calcium above 400 ppm causes cloudy water and scale deposits on surfaces and equipment. Dose gradually and retest before adding more. High calcium can only be corrected by diluting with fresh water.
Q: How often will I need to adjust calcium hardness?
A: Calcium hardness is stable and doesn't deplete quickly. Test monthly and after significant water top-ups or refills. Spas need more frequent testing due to evaporation concentrating the water.
Q: Is this safe for all pool types?
A: Yes - safe for concrete, fibreglass, vinyl liner, and tiled pools, and all spa pool types when used as directed.
Pickup and Delivery
Perfect Pools Service Warehouse - 15C Douglas Alexander Parade, Albany, Auckland
Hours: Mon-Fri 9am-4pm | Sat 10am-2pm
NZ-wide delivery available. Charges calculated at checkout.
Questions? Email perfectpoolsnz@gmail.com or visit our contact page.
