CO₂ ranges that include input uncertainty
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CO2 Calculator: Planted Tank
A range your water tests can support.
CO₂ Calculator helps planted-tank keepers interpret pH, carbonate hardness and temperature without hiding measurement uncertainty. Results appear as ranges, and unsuitable water chemistry blocks the KH/pH method. Guided degassing, delta-pH sessions and a drop-checker reference provide additional ways to review your tank readings.
Free to download · USD store listing
iOS 17.0+ · See the App Store for current pricing and in-app purchases.
YOUR QUESTION. A CLEAR ANSWER.
How do I estimate CO₂ in a planted aquarium from pH and KH?
CO₂ Calculator uses your test inputs and their resolution to return an estimated range, while checking whether the KH/pH method applies to your tank.
Get started with CO₂ Calculator.
- Enter your tank’s water-test readings, temperature and relevant chemistry declarations before selecting an applicable calculation method.
- Review the estimated range and method warnings rather than interpreting one number as an exact measurement.
- Follow guided degassing for a delta-pH session when appropriate, and save readings to follow your tank over time.
Here’s what you can do.
Chemistry checks for the KH/pH method
Guided degassing and delta-pH sessions
A look inside.
Original screenshots from the App Store.
Good to know.
Can I use the KH/pH calculation with aquasoil?
The app blocks that calculation when buffers such as aquasoil or peat invalidate its assumptions and points to alternative methods.
Does the app measure CO₂ itself?
No. You supply readings from a test kit or probe. The app interprets inputs and does not replace water testing.
Where can I download CO₂ Calculator?
The app is available on the Apple App Store. The listing has the current version, regional availability, privacy details, and in-app purchases. App Store ↗
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Store details checked September 16, 2026.