Measurement
Your tank volume is uncertain: show the calculation as an interval
A worked sensitivity check shows how uncertain water volume changes a proportional result without choosing a dose.
By FishyMag · Published
Worked arithmetic example · Not a clinical review or treatment recommendation.
Quick answer
If a proportional calculation depends on an uncertain water volume, keep the plausible bounds visible. An interval shows sensitivity to that input. It does not tell you which volume or dose is appropriate.
Write the input uncertainty first
Suppose a keeper’s current evidence supports only a 35 L to 45 L volume interval. Write down how the bounds were obtained and why the difference remains unresolved. Do not label a guessed range as a statistical confidence interval. It is a description of the input evidence, not a measurement certificate.
Apply the same arithmetic to each endpoint
For a fictional scaling rule of 2 mL per 10 L, the factor is 0.2 mL per litre. Multiplying both bounds gives 7 mL and 9 mL. The midpoint calculation at 40 L is 8 mL, but the midpoint does not become the correct choice just because it sits between the endpoints. This fictional rule is not attached to an aquarium product.
| Input volume | Fictional factor | Calculated quantity |
|---|---|---|
| 35 L lower bound | 0.2 mL/L | 7 mL |
| 40 L midpoint | 0.2 mL/L | 8 mL |
| 45 L upper bound | 0.2 mL/L | 9 mL |
Do not turn sensitivity into permission
The 2 mL spread in this example comes from volume uncertainty alone. It does not include device error, product concentration differences or label conditions. Nor does a lower calculated quantity establish safety. Use the spread to identify a weak input, then improve the volume record or seek guidance before relying on it.
Keep a revision trail
If a later fill record supports a different operating volume, record the method, configuration and date, then mark the older interval as superseded. Retain it in the history so another keeper can understand earlier calculations. The volume calculator can check endpoints separately; it does not determine plausible bounds from the tank’s advertised size.
Use your own details
Your tank volume is uncertain: show the calculation as an interval worksheet
Download the editable text file, fill it in on your device and keep it with the relevant record. This blank worksheet records your information; it does not verify entries or approve treatment.
- Operating configuration and date
- Lower volume bound, unit and supporting method
- Upper volume bound, unit and supporting method
- Scaling rule and units, if applicable
- Endpoint calculations and unresolved input
- Replacement measurement and revision date
Put it into practice
Your checklist
- Explain where both volume bounds came from.
- Apply identical units and the same factor to both endpoints.
- Resolve weak inputs instead of treating the midpoint as a recommendation.
Sources and scope
This article distinguishes manufacturer statements from FishyMag’s own workflows and arithmetic examples. Linked formulation records retain their own evidence dates; publishing this article does not refresh those records.
AI-assisted writing and development. Not hands-on product testing or veterinary review. How we publish →
FishyMag reports what manufacturers say, quoted and linked. It does not diagnose illness or recommend a treatment, and it never infers that a product is safe from the absence of a warning — where no statement exists, it says so.
Formulations change. Always read the label on the bottle in your hand, and contact the manufacturer if your tank contains anything valuable or unusual.