CO2 Consumption & Cylinder Runtime Calculator
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CO2 Consumption & Cylinder Runtime Calculator
Estimate CO₂ consumption and cylinder runtime.
How long will my CO₂ cylinder last?
Why calculate CO₂ consumption?
Knowing your CO₂ consumption helps you plan refills, budget for ongoing costs, and ensure uninterrupted CO₂ supply for your planted aquarium. Running out of CO₂ mid-week can trigger algae problems and stress plants. This calculator estimates your daily usage and predicts when you will need a refill based on your bubble rate and cylinder size.
How the calculation works
A CO₂ bubble from a standard bubble counter contains approximately 0.06 mL of gas (this varies slightly by equipment). The calculation converts bubbles to grams of CO₂:
Daily CO₂ (g) = BPS × 3600 × Hours × Bubble volume (mL) × CO₂ density (0.00198 g/mL)
Understanding bubble rates (BPS)
| Bubble rate | Typical tank size | Daily usage (approx.) |
|---|---|---|
| 1 BPS | 20–60 L | ~3–5 g |
| 2–3 BPS | 60–150 L | ~6–15 g |
| 4–6 BPS | 150–300 L | ~15–30 g |
| 8+ BPS | 300+ L | ~30+ g |
Common CO₂ cylinder sizes
- Disposable cartridges: 88–95 g – convenient but expensive per gram
- Small refillable: 350–500 g – good for nano tanks
- Standard: 2–3 kg (2000–3000 g) – most common for home aquariums
- Large: 5–10 kg – economical for large tanks or multiple setups
Expected cylinder runtime examples
| Cylinder | At 1 BPS / 8h | At 3 BPS / 8h |
|---|---|---|
| 500 g | ~3–4 months | ~1 month |
| 2 kg | ~12–16 months | ~4–5 months |
| 5 kg | ~2–3 years | ~10–12 months |
Tips for efficient CO₂ usage
- Use a solenoid valve with a timer – CO₂ is only needed during the light period
- Clean your diffuser regularly – clogged diffusers create larger, less efficient bubbles
- Position diffuser under filter intake for maximum dissolution
- Plan refills in advance – running out of CO₂ suddenly can shock plants and promote algae