Plan refills before irrigation or enrichment runs. Use mass or pressure inputs for flexible estimates. Know your minutes, hours, and days at a glance.
| Gas | Method | Mass (kg) | Flow (L/min) | Duty (%) | Runtime (hours) | Runtime (days) |
|---|---|---|---|---|---|---|
| CO₂ | Mass-based | 5 | 2 | 50 | 42.2 | 1.76 |
1) Convert flow to L/min
2) Effective flow
EffectiveFlow = Flow(L/min) × Outlets × (DutyCycle/100) × (1 + Extra/100)
3) Available gas
4) Reserve buffer and runtime
Runtime(min) = AvailableAfterReserve(L) ÷ EffectiveFlow(L/min)
A cylinder’s usable volume is best planned in liters of free gas. Using the mass method, free gas(L)=mass/density×1000. For example, 5 kg of CO₂ at 1.977 kg/m³ equals about 2,530 L. That volume can support enrichment, pneumatic misting, or purge lines, depending on your flow and duty settings. If you refill by weight, log the mass each time weekly.
Runtime depends on effective flow, not the label on your regulator. Effective flow multiplies the base flow by the number of outlets, then scales by duty cycle and any extra allowance. Example: 2 L/min with two outlets at 40% duty becomes 1.6 L/min effective. Small adjustments here often change refill timing more than cylinder size. When using CFH, remember 1 CFH is about 0.472 L/min.
When you only know water capacity and pressures, the pressure method estimates free gas using Pdiff/Patm and a temperature correction. A warmer cylinder reduces the calculated free volume at a fixed pressure reading. Enter a cylinder temperature and keep reference temperature constant to compare summer and winter schedules.
Garden setups can lose gas through micro leaks, quick-connects, or solenoid seats. Add an extra usage percentage to represent loss, then apply a reserve buffer so you refill before reaching the minimum operating pressure. A 10% reserve is a common planning start, while troubleshooting systems may need 20% until stable. Recheck fittings with soapy water after hose changes.
Convert runtime into a refill calendar by matching hours or days to your operating schedule. If you log refill cost, divide cost by runtime hours to estimate operating cost per hour. Use that figure to compare alternative flows, shorter enrichment windows, or shared manifolds across zones. For critical crops, plan your next refill at half the calculated runtime.
1) Which method should I use for CO₂ enrichment?
Use the mass method whenever you know the filled mass. CO₂ pressure can stay fairly flat while liquid remains, so pressure readings may mislead. The pressure method is useful for non‑liquefied gases and quick estimates.
2) How do I convert CFH to L/min?
Multiply CFH by 28.316846592 to get liters per hour, then divide by 60. The calculator does this automatically when you select CFH, so you can enter regulator settings directly.
3) What does duty cycle mean in gardening use?
Duty cycle is the percent of time gas actually flows. A solenoid running 10 minutes per hour is about 16.7% duty. Lower duty increases runtime without changing the cylinder size.
4) Why add extra usage or leak percent?
Extra usage accounts for small leaks, purge bursts, and regulator drift. Start with 5–10% if your system is tight, and increase it while troubleshooting. Reducing leaks often saves more than buying a larger cylinder.
5) Can I estimate runtime for several zones?
Yes. Enter the number of outlets that run simultaneously, or increase flow to match total combined demand. If zones run one at a time, use duty cycle to represent the schedule and keep outlets at one.
6) Why might real runtime differ from the estimate?
Temperature swings, regulator behavior, hose losses, and changing plant demand can alter flow. Treat the result as a planning baseline, then refine inputs using a short timed test and your refill records.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.