Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Dissolved CO2 (ppm)
19.0
Assessment
In target range
Suggested bubbles/second
4.0
Bubbles per hour
14,400
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter tank volume (gal).
- 2Enter carbonate hardness (kh) (dKH).
- 3Enter ph with co2 on.
- 4Enter light intensity (1 low – 3 high).
- 5Read your dissolved co2 (ppm) on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Estimate target bubbles per second by tank volume, plus the dissolved CO2 implied by your KH and pH readings.
Worked example
Using the values the calculator loads with:
Inputs
- Tank volume: 40 gal
- Carbonate hardness (KH): 4 dKH
- pH with CO2 on: 6.8
- Light intensity (1 low – 3 high): 2
Results
- Dissolved CO2 (ppm): 19
- Assessment: In target range
- Suggested bubbles/second: 4
- Bubbles per hour: 14,400
What each field means
Inputs
- Tank volume (gal)
- The tank volume used in the calculation, measured in gal. Starts at 40 gal so you have a working example on load.
- Carbonate hardness (KH) (dKH)
- The carbonate hardness (kh) used in the calculation, measured in dKH. Starts at 4 dKH so you have a working example on load.
- pH with CO2 on
- The ph with co2 on used in the calculation. Starts at 6.8 so you have a working example on load.
- Light intensity (1 low – 3 high)
- The light intensity (1 low – 3 high) used in the calculation. Starts at 2 so you have a working example on load. Accepted range: 1–3.
Results
- Dissolved CO2 (ppm)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Assessment
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Suggested bubbles/second
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Bubbles per hour
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the aquarium co2 dosing calculator work?
Estimate target bubbles per second by tank volume, plus the dissolved CO2 implied by your KH and pH readings. The underlying maths is: CO2 ppm ≈ 3 × KH × 10^(7 − pH).
What do I need to enter?
4 values: tank volume, carbonate hardness (kh), ph with co2 on, and light intensity (1 low – 3 high). Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the dissolved co2 (ppm) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Aquarium CO2 Dosing Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/aquascape-co2
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/aquascape-co2" target="_blank" rel="noopener">Aquarium CO2 Dosing Calculator — RevenueLab</a> (2026).</p>
Source: [Aquarium CO2 Dosing Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/aquascape-co2) (2026).