Aquarium CO2 Calculator
Estimate dissolved CO₂ from pH and carbonate hardness.
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What this tool does
Estimate dissolved CO₂ from pH and carbonate hardness. Only applies when carbonate chemistry dominates buffering; other acids, phosphate buffers and substrates can invalidate the estimate.
How to use the Aquarium CO2 Calculator
- Enter or select carbonate hardness (dkh).
- Enter or select measured ph.
- Read the calculated result; change any measurement to compare alternatives.
Formula
CO2 mg/L≈3×KH×10^(7−pH)
- kh
- Carbonate hardness (dKH)
- ph
- Measured pH
Only applies when carbonate chemistry dominates buffering; other acids, phosphate buffers and substrates can invalidate the estimate.
Worked example
For aquarium co2 calculator, the following measurements illustrate the exact method: Carbonate hardness (dKH): 4; Measured pH: 6.8.
Inputs
- Carbonate hardness (dKH)4
- Measured pH6.8
Result
- Estimated CO₂ (mg/L)19.02
Results explained
- Estimated CO₂ (mg/L)
- Estimated CO₂ (mg/L) from the formula above. Only applies when carbonate chemistry dominates buffering; other acids, phosphate buffers and substrates can invalidate the estimate.
Frequently asked questions
CO2 mg/L≈3×KH×10^(7−pH)
No. Individual animals differ. Consult your veterinarian before changing feeding or treatment, and seek immediate veterinary care for poisoning concerns.
Only applies when carbonate chemistry dominates buffering; other acids, phosphate buffers and substrates can invalidate the estimate.
Use current measured weight, actual food or product label values, and the dates or water readings requested. Check units before entering any value.
Verify if the animal is ill, pregnant, growing unusually, or on a special diet. Aquarium chemistry changes should be measured gradually and checked against product instructions.