







Hot Tub & Spa Total Alkalinity Plus (Sodium Bicarbonate)
Test All Water Hot Tub & Spa Total Alkalinity Plus is an essential water treatment product designed to raise and stabilise the total alkalinity levels in hot tubs and spas.
Proper alkalinity is crucial for maintaining balanced water chemistry, preventing pH fluctuations, and ensuring a safe and comfortable bathing experience. When the Total Alkalinity levels drop too low, changes in the pH can happen which can cause corrosion and harmful or disagreeable bathing conditions.
The ideal levels of Total Alkalinity in Hot Tubs and Spa is between 80-140 mg/l (ppm).
This high-quality sodium bicarbonate formulation is easy to use and provides reliable results, making it an indispensable part of your spa maintenance routine.
Key Features:
- Raises total alkalinity
- Prevents pH fluctuations
- Enhances water clarity
- Easy to use
- Protects spa equipment
- Safe and gentle
Ideal for use in:
- Routine maintenance
- Problem solving
- Seasonal opening and closing
Total alkalinity is a measurement of the waters ability to resist pH change.
If the total alkalinity is low then the pH can fluctuate making it difficult to control and maintain at the ideal level.
If the total alkalinity is high then the pH can be difficult to change and will keep rising. A high total alkalinity can also lead to the formation of a bicarbonate scale on pool surfaces, within pipework and in plant room equipment.
If the total alkalinity of your pool water is below 80mg/l it should be increased using Blue Horizons TA Raiser, the table below indicates the dosage quantities required:
Total Alkalinity Increaser Dosing Rates | |||||||
Pool Volume | To Increase Total Alkalinity by: | ||||||
Litres | Gallons | 10 mg/l | 25 mg/l | 50 mg/l | |||
4,545 | 1,000 | 81g | 203g | 405g | |||
11,364 | 2,500 | 203g | 508g | 1.01g | |||
22,727 | 5,000 | 450g | 1.01kg | 4.05kg | |||
45,455 | 10,000 | 810g | 2.02kg | 4.05kg |

Frequently Asked Questions
Clear answers to help you choose the right water testing solution with confidence
Which brands of water testing kits do you supply?
Do you provide kits for both home and professional use?
Yes — whether you’re a pool or spa owner, aquarium keeper, utility company, or a university laboratory, we have the right solution for your needs.
Can I arrange servicing or calibration for my photometer?
Absolutely. We also provide servicing and calibration to keep your photometers accurate and reliable.
How quickly do you dispatch orders?
Orders placed before 2:30 pm (Monday–Friday) are dispatched the same day. We also ship on Saturdays for your convenience.
Which couriers do you use for delivery?
We deliver through UPS, DPD, and Royal Mail. You can also choose to upgrade to next-day delivery at checkout.
What is your return policy?
We accept returns within 14 days of delivery provided the items are unused, in their original packaging, and in resalable condition. Please contact our team before returning any items.
Can I place bulk or business orders?
Yes, we welcome bulk, trade, and institutional orders. For tailored pricing or large quantities, please get in touch with us directly.
How can I get help if I’m unsure which kit to buy?
You can call us at 📞 +44 (0)115888 2726 and our team will guide you in choosing the most suitable kit for your needs.