SpaGuard Spa Calcium Hardness Increaser 12 oz 6-Pack — Granular Calcium Chloride, Raises Hardness Quickly

SpaGuard Calcium Hardness Increaser (12 oz) raises spa calcium hardness quickly and reliably to protect equipment and surfaces.

Keeping the right calcium hardness in your hot tub prevents corrosion of metal parts and etching of plaster surfaces. SpaGuard’s granular calcium chloride formula is designed for spa owners who want a simple, doseable solution: 1 tablespoon per 100 gallons raises calcium hardness about 25 ppm. Sold here as a convenient six-pack of 12 oz containers, this product works alongside common sanitizers like chlorine and bromine and integrates into normal spa maintenance routines.

How do I use this product safely and effectively?

Measure your pool or spa volume and test calcium hardness before adding any chemicals. Apply the recommended amount directly to the water, do not pre-dissolve, and run the circulation system for at least 30 minutes to distribute the granules.

• Test calcium hardness with an accurate kit prior to dosing.
• Add 1 tablespoon per 100 gallons to raise hardness roughly 25 ppm.
• Do not pre-dissolve; sprinkle granules across the water surface and brush away any that cling to the shell.
• Run the circulation pump for 30 minutes after application for full dissolution.

Why raise calcium hardness in a hot tub?

Water with very low calcium hardness is aggressive and can corrode heaters, jets, and plumbing, and may etch plaster or shell surfaces. Raising hardness stabilizes the water chemistry so equipment and surfaces last longer and perform better.

• Prevents metallic corrosion of heating elements and fittings.
• Reduces risk of surface etching or pitting in plaster and shell finishes.
• Helps maintain stable water chemistry between routine treatments.

How much will one 12 oz container treat, and how often should I check levels?

Each 12 oz container contains concentrated granular calcium chloride; dosing depends on your spa’s volume and current hardness level. Check calcium hardness after any major water top-off or refill and incorporate it into your monthly water-balance checks.

• 1 tbsp per 100 gallons increases hardness by about 25 ppm.
• Re-check hardness after treatment and during monthly maintenance.
• Keep product on hand for periodic adjustments after draining or heavy dilution.

Will this product work with my sanitizer system?

SpaGuard Calcium Hardness Increaser is compatible with common sanitizers including chlorine, bromine, ozone, and biguanide systems. It is formulated to integrate without interfering with standard spa disinfectants when used according to instructions.

• Safe to use alongside chlorine and bromine sanitizers.
• Compatible with ozone and biguanide treatments.
• Always follow label directions and re-test water after dosing.

Who is this for: SpaGuard Calcium Hardness Increaser is for spa owners and service professionals who need a straightforward, granular solution to correct low calcium hardness. It’s well suited for those maintaining hot tubs, small plunge pools, or spa systems who want to protect pumps, heaters, jets, and surfaces from corrosive, low-hardness water. Buy a six-pack to keep spare containers available for routine adjustments, seasonal water changes, or when topping off your spa.