Enriching your indoor garden with Carbon Dioxide (CO2) can increase plant growth rates by up to 30% and significantly boost your final yields. However, CO2 systems are only effective when managed precisely. Running out of gas mid-bloom or setting your flow rate too low results in wasted potential. Conversely, a regulator set too high simply dumps expensive gas down the exhaust fan.
Our CO2 Calculator takes the guesswork out of enrichment. By calculating the gas volume of your tank (lbs to cu ft) and matching it to your regulator’s flow rate (SCFH), you can predict exactly when you need to head to the brew shop for a refill.
CO2 Tank Duration Calculator
How to Use the CO2 Tank Calculator
- Tank Size: Select the weight of your CO2 cylinder. Standard garden tanks are usually 20 lbs.
- Flow Rate (SCFH): Look at the ball-float gauge on your regulator. This is measured in Standard Cubic Feet per Hour.
- Burn Time: How many minutes per hour is your solenoid open? Most growers use a controller to “pulse” CO2 for 15-20 minutes every hour.
- Room Size: Enter your length, width, and height to unlock our “Secret Sauce” flow rate suggestion.
Why We Built This: The “Secret Sauce” of Saturation
The “Secret Sauce” of our tool is the Automated Regulator Suggestion. Most growers struggle to find the right balance between room volume and flow rate.
Our tool uses your room’s total cubic footage to calculate the exact SCFH setting required to reach 1,200 PPM (the “sweet spot” for most fruiting plants) within a 15-minute window. This ensures you saturate the canopy quickly without overshooting and wasting gas.
Educational Guide: The Science of CO2 Enrichment
Plants “breathe” CO2 through microscopic pores in their leaves called stomata. In a standard outdoor environment, CO2 levels are roughly 400 PPM. In a sealed indoor garden, plants can consume all available CO2 in less than an hour, causing growth to stall.
The Ideal Enrichment Range
Most garden crops respond best to levels between 1,000 and 1,500 PPM. Levels above 2,000 PPM can become toxic to plants, and levels above 5,000 PPM are dangerous for humans. Always use a dedicated CO2 monitor with an emergency shut-off solenoid.
Temperature and Light Coordination
Enriching with CO2 is only effective if your plants have high light intensity (high PPFD) and slightly warmer temperatures. When running 1,200 PPM of CO2, you can safely raise your room temperature to 82°F–85°F, which speeds up the plant’s metabolic processes and photon absorption.
Frequently Asked Questions
Q: How many cubic feet of gas are in a 20lb CO2 tank?
A: One pound of liquid CO2 expands into approximately 8.74 cubic feet of gas. Therefore, a 20lb tank holds roughly 175 cubic feet of CO2.
Q: Do I need to run CO2 at night?
A: No. Plants only consume CO2 during photosynthesis (when the lights are on). Running CO2 during the dark cycle is a waste of gas and can potentially harm the plants by displacing oxygen needed for root respiration.
Q: Should I turn off my exhaust fan when using CO2?
A: Yes. For a CO2 system to be effective, the room must be “sealed.” If your exhaust fan is pulling air out, your expensive CO2 is being sucked out before the plants can use it. Most growers use a “flip-flop” controller that turns off the fans when the CO2 solenoid is active.
