Active Air CO2 system with timer .2-2/hour

The Active Air CO2 System with Timer is a self-contained CO2 enrichment unit designed for small to medium indoor grow spaces. It delivers CO2 at a programmable, adjustable rate of 0.2 to 2.0 cubic feet per hour, and uses a built-in timer to maintain target CO2 levels automatically — without requiring a separate CO2 controller. Made by Hydrofarm under the Active Air brand, it is one of the more straightforward entry-level CO2 systems available for hobby and small commercial cultivators.

Active Air CO2 System Specifications

Specification	Value
Brand	Hydrofarm / Active Air
SKU	COSYS
CO2 Output Range	0.2 – 2.0 cu ft/hour (adjustable)
Timer	Built-in programmable timer included
Intended Area Size	Small to medium grow spaces
Weight	3.50 lbs
Category	CO2 Systems — Climate & Environment

Why Choose the Active Air CO2 System

CO2 enrichment raises ambient CO2 concentration above the atmospheric baseline of roughly 400 ppm, which can support faster photosynthesis when plants have adequate light, water, and nutrients. The Active Air CO2 System addresses this in a few practical ways:

• Integrated timer: The programmable timer is built into the unit rather than sold separately. You can schedule CO2 delivery to coincide with your light-on period, which is when plants are photosynthetically active and can use elevated CO2 effectively.
• Adjustable output rate: The 0.2–2.0 cu ft/hour range lets you dial output to match your room volume. A smaller tent running at 0.2 cu ft/hour will reach target CO2 levels more gradually than a larger space running at 2.0 cu ft/hour — the adjustment gives you control over that balance.
• Designed for small to medium spaces: The system is sized and rated for hobby-scale and small commercial rooms, not warehouse grows. If your canopy footprint is measured in square feet rather than hundreds of square feet, this unit is in the right class.
• Simple operation: The canonical description characterizes this as a user-friendly, easy-to-operate system. There is no separate CO2 controller to wire in — the timer handles the automation.
• Hydrofarm / Active Air sourcing: Hydrofarm is a long-established horticultural distributor with a broad dealer network, which generally means replacement parts and support are accessible through standard hydro retail channels.

Best Uses for the Active Air CO2 System

This system fits a specific profile of grower and setup. It is most useful when the following conditions apply:

• Sealed or near-sealed grow rooms: CO2 enrichment is most effective in an environment where ambient CO2 does not escape rapidly. In a tightly sealed tent or room, the timer-metered output can hold elevated levels between on-cycles. In a loosely ventilated space, CO2 bleeds out before it can accumulate to useful levels.
• High-light environments: Elevated CO2 only benefits plants when they are not already light-limited. If you are running high-output grow lights — HPS, CMH, or LED fixtures above roughly 400 µmol/m²/s — CO2 enrichment can contribute meaningfully to growth rate. At lower light levels, the effect is negligible.
• Small to medium canopy footprints: Rooms or tents with a canopy area up to approximately 50–100 sq ft are the practical target for this output range. Larger spaces would require higher-volume CO2 delivery (tanks with external regulators, or burners) to maintain consistent enrichment across the room.
• Growers who want automation without complexity: The built-in timer removes the need for a separate CO2 controller. For growers who do not need parts-per-million monitoring and want a set-and-schedule approach, this is a simpler entry point than a sensor-based controller system.
• Indoor tent and room grows: Whether you are growing in a dedicated grow tent or a converted room, this system drops in without requiring special installation beyond connecting it to a CO2 source and setting the timer schedule.

For climate monitoring alongside CO2 delivery, a dedicated humidity management tool such as the Ideal Air Pro Series dehumidifier condensate pump can complement this system in sealed environments where humidity tends to build.

Compatibility and Operating Range

The Active Air CO2 System with Timer (COSYS) is intended for indoor horticultural use in small to medium grow environments. Based on the canonical product data available:

• CO2 source compatibility: This system is designed to connect to a standard CO2 tank or cylinder. It is not a CO2 generator (burner) — it is a flow-control and timer assembly that regulates release from a compressed CO2 supply. You will need a separate CO2 tank and, typically, a CGA-320 CO2 tank fitting. (Note: tank fittings and tank type should be confirmed with the retailer or manufacturer documentation at time of purchase.)
• Room volume: At the rated output of 0.2–2.0 cu ft/hour, the system is appropriate for typical hobby grow rooms. As a rough frame of reference, a standard 4×8 ft tent with an 8 ft ceiling has a volume of approximately 256 cu ft. At higher output settings, this system can deliver meaningful CO2 enrichment in spaces of that scale.
• Use with air circulation: CO2 is denser than air and can stratify near the floor if not circulated. Pairing this system with an oscillating or pedestal fan helps distribute CO2 evenly across the canopy.
• Not rated for outdoor use: CO2 enrichment is ineffective in open or unenclosed environments where gas dissipates before concentrations can rise.

Manufacturer-published electrical specifications, exact connection type, and pressure ratings are not present in the available canonical data. Refer to the documentation included with the unit or contact Hydrofarm for detailed technical specifications before purchase if these are decision-critical for your setup.

Sources & Further Reading