HTH Spa Alkalinity Up granular 1.25 lb — Raises total alkalinity fast, stabilizes pH for clearer water

HTH Spa Alkalinity Up is a fast-acting treatment that raises total alkalinity in spa water to stabilize pH and protect surfaces and equipment.

Low alkalinity can cause rapid pH swings, corrosion, cloudy water and discomfort for bathers. HTH Spa Alkalinity Up (1.25 lbs) is a granular formula designed to quickly increase total alkalinity and help keep pH within the desired range for balanced, comfortable spa water. It’s compatible with bromine, chlorine and biguanide systems and works alongside routine testing and sanitizing to maintain a healthy hot tub environment.

How do I use HTH Spa Alkalinity Up safely and effectively?

Test your water first using HTH Spa Test Strips. If total alkalinity is below 80 ppm, add the recommended dosage directly to circulating spa water, allow the pump to run, then retest after 1–3 hours; repeat until alkalinity reaches 80–120 ppm.

• Test total alkalinity before treatment and every few days.
• Add granules slowly to circulating water; follow package dosage instructions.
• Run circulation 1–3 hours, then retest and repeat if needed.
• Do not overdosed; adjust with pH decreaser if pH rises too high.

Will this product affect my sanitizer or spa equipment?

HTH Spa Alkalinity Up is formulated to be compatible with common sanitizers and will not interfere with bromine, chlorine or biguanide systems when used as directed. By stabilizing alkalinity and limiting pH swings, it can help reduce stress on heaters, pumps and filters, extending component life.

• Compatible with chlorine, bromine and biguanide sanitizer regimes.
• Helps prevent scale and corrosion caused by fluctuating pH.
• Supports clearer water, easing filter workload and maintenance.

How quickly will I notice results after applying Alkalinity Up?

Alkalinity changes are typically measurable within a few hours of treatment once water has circulated. Most users see total alkalinity return to the target 80–120 ppm after one or two treatments, depending on the initial level and spa volume.

• Allow 1–3 hours of circulation before retesting.
• Repeat dosing if alkalinity remains below recommended range.
• Follow up with regular testing twice weekly to maintain balance.

Who is this for: HTH Spa Alkalinity Up is aimed at hot tub and spa owners who test and maintain water chemistry themselves and want a reliable solution to raise total alkalinity and reduce pH instability. It’s suited for private spa owners, rental property managers, and service professionals using chlorine, bromine or biguanide sanitation who need a straightforward, effective alkalinity increaser to protect equipment, improve comfort and keep water clear.