Calcium Hardness Increaser 1kg | Calcium Chloride Spa & Pool
Soft water foaming up your spa or corroding your equipment? Calcium Hardness Increaser (Calcium Chloride) is the essential treatment that protects your spa shell, heater, jets, and fittings from the damaging effects of low-calcium water - while eliminating the foaming and etching that soft water causes.
The 1kg pail is the perfect size for spa owners and hot tub users. Water with low calcium hardness is aggressive - it actively leaches calcium from your spa surfaces and equipment. The result is pitting, etching, foaming, and costly equipment damage. A correct calcium hardness level of 150-250 ppm is your first line of defence.
Product Specifications
| Active Ingredient | Calcium Chloride |
| Size | 1kg resealable pail |
| Suitable For | Spa pools, hot tubs, swim spas, and swimming pools |
| Spa Dosage | 15g per 1,000L raises calcium hardness by approx. 10 ppm |
| Pool Dosage | 300g per 20,000L raises calcium hardness by approx. 10 ppm |
| Target Range (Spas) | 150-250 ppm |
| Target Range (Pools) | 200-400 ppm (varies by surface type) |
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 spa life
- Ideal range for spas: 150-250 ppm | Ideal range for pools: 200-400 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 spa pools, hot tubs, swim spas, and swimming pools.
- Prevents Corrosion. Protects heater elements, pumps, jets, and fittings from soft water damage.
- Reduces Foaming. Eliminates foaming caused by soft, low-calcium water.
- 1kg Resealable Pail. Ideal size for spas and hot tubs.
Dosing Guide
Spa Pools and Hot Tubs (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 warm 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
- 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 (this product) - ideal for spas, hot tubs, or small top-up doses.
- 4kg Pail - 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
- Refer to the Safety Data Sheet (SDS) for full handling instructions
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) 1kg - adjust pH to the ideal 7.2-7.8 range after balancing calcium.
- 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 250 ppm in spas causes cloudy water and scale deposits. Dose gradually and retest before adding more. High calcium can only be corrected by diluting with fresh water.
Q: How long will a 1kg pail last?
A: For a 1,000L spa starting at 100 ppm and targeting 200 ppm, you need approximately 150g. A 1kg pail provides roughly 6-7 full treatments from scratch, or many more for small top-up doses.
Q: Is this safe for all spa types?
A: Yes - safe for acrylic, fibreglass, and inflatable spa pools, and all hot tub 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.
