Find the volume
Use the manufacturer’s figure or estimate the water area using inner length × inner width × average water depth.
Dosing calculator
The right dose. No guesswork required.
Enter your water volume — or estimate it from the inner dimensions. You’ll instantly see your weekly care dose, bottle coverage, and first-year usage.
- A clear result in seconds
- Start phase included
- For spas up to 6,000 litres
Your spa
How would you like to enter the water volume?
For the most accurate figure, check your spa manual.
Your care plan
30 mlper week
for approx. 1,000 L
Start phase3 × 30 mlon three consecutive days
1 litre lasts33 weeksat the weekly care dose
First-year usage2 bottles1.65 L · including the 90 ml start phase
Guide value based on WhirlBiotic consumer directions. For intensive use or commercial installations, please follow the product instructions.
Clear calculation
How we calculate your result.
The calculator uses the same dosing tiers as our consumer guide and turns them into a practical care plan.
Match the dose tier
The calculated volume is assigned to one of four weekly care tiers ranging from 30 to 150 ml.
Plan your supply
From the weekly dose and start phase, we estimate bottle coverage and your approximate first-year needs.
Weekly dosing tiers
| Water volume | WhirlBiotic per week |
|---|---|
| Up to 1,000 L | 30 ml |
| 1,001–2,000 L | 50 ml |
| 2,001–4,000 L | 100 ml |
| 4,001–6,000 L | 150 ml |
After a longer period out of use or under unusual load, an adjusted application may be useful.
Ready for your routine?
Water care that fits into your life.
Choose the right size for your calculated needs, or read the complete application guide first.