pH Decreaser Sodium Bisulphate 10kg | Pool & Spa pH Down

Maintain safe and balanced water chemistry in your swimming pool or spa pool with pH Decreaser (Sodium Bisulphate). When pH rises above 7.6, chlorine loses up to 90% of its effectiveness, water turns cloudy, and scale builds on surfaces and fittings. A quick dose of Sodium Bisulphate brings it right back into range.

The 10kg pail is the best value option for large pools or frequent use, providing approximately 20 full pool doses for a 50,000L pool.

Product Specifications

Key Features

• Sodium Bisulphate Formula. Fast-acting granular pH reducer, the industry standard for lowering pool and spa pH.
• Fast-Acting. Lowers pH within hours of application.
• Dual-Purpose. Suitable for swimming pools and spa pools of all types.
• Prevents Scale Buildup. Stops calcium deposits forming on pool surfaces, fittings, and equipment.
• Best Value 10kg Size. Lowest cost per kg in the range, ideal for large pools or frequent use.

Dosing Guide

Swimming Pools:

• Add 500g per 50,000L to lower pH by approximately 0.5
• Pre-dissolve in a bucket of water before adding to the pool
• Pour near the skimmer or return jet with pump running
• Allow 6 hours of circulation, then retest before adding more
• Never add more than 500g per 50,000L in a single dose

Spa Pools:

• Add 10g per 1,000L to lower pH by approximately 0.5
• Pre-dissolve in a small bucket of water before adding
• Run jets while dosing for even distribution
• Retest after 30 minutes before re-dosing

Available Sizes

• 1kg Pail - ideal for spas or small top-up doses
• 4kg Pail - most popular for regular pool maintenance
• 10kg Pail (this product) - best value for large pools or frequent use

Recommended Accessories

• 5-in-1 Test Strips - always test pH before and after dosing.
• Alkalinity Increaser 4kg - stabilise Total Alkalinity first to make pH easier to control.
• pH Increaser (Soda Ash) 4kg - use when pH drops too low and needs raising back to 7.2-7.6.
• Crystalline Chlorine 4kg - sanitise at the correct pH for maximum effectiveness.

Frequently Asked Questions

Q: How quickly does pH Decreaser work?
A: pH begins dropping within 30-60 minutes of application. Allow 6 hours of full circulation before retesting and re-dosing if needed.

Q: Can I add pH Decreaser and chlorine at the same time?
A: No, always adjust pH first, wait 6 hours, then add chlorine. Adding both together reduces the effectiveness of both chemicals.

Q: What if I add too much and pH drops too low?
A: Use pH Increaser (Soda Ash) to bring it back up. Always dose gradually and retest before adding more to avoid overcorrecting.

Q: How long will a 10kg pail last?
A: For a 50,000L pool needing a 0.5 reduction in pH, you need 500g per dose. A 10kg pail provides approximately 20 full pool doses, enough for a full season of regular adjustments.

Q: Why is my pH always rising?
A: Common causes include saltwater chlorinators, high Total Alkalinity, and aeration from jets or waterfalls. Check your Total Alkalinity first, if it is above 120 ppm, lowering it will help stabilise pH naturally.

Q: Is Sodium Bisulphate 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.