Active Air 6" x 16" Carbon Filter - 400 CFM

This filter is rated for 400 CFM and uses a 6" attached flange, so it pairs directly with the Active Air 6" Inline Duct Fan - 400 CFM. Running a fan that exceeds the filter's CFM rating will push air through the carbon too quickly for full odor adsorption — match or slightly underrate your fan for best results.

Australian granular carbon is widely regarded in the industry for its high surface area and micro-pore density, which directly determines how many odor molecules the carbon can capture per gram. Virgin (unused, non-recycled) carbon ensures the full adsorption capacity is available from day one rather than being partially spent from prior industrial use.

Carbon filters are designed to work on the intake side of an inline fan — air is pulled through the carbon bed before passing through the fan and out of the space. To complete your ventilation setup, we recommend using Active Air premium ducting for a secure, airtight connection. Pushing air through the filter is possible but generally less efficient.

The most reliable indicator is odor breakthrough — when you begin to detect grow room smells outside your exhaust, the carbon bed is saturated and needs replacement. Under typical conditions this occurs within one to two years, though running at maximum speed continuously will shorten that window.

The pre-filter sleeve wraps the outside of the carbon filter and catches dust, hair, and other airborne particulates. Keeping the pre-filter clean is essential; you can find a replacement Active Air pre-filter if your original sleeve becomes too clogged to wash and reuse.

Yes — sustained high humidity (above 70% RH) is a primary factor that shortens carbon filter life. Maintaining proper humidity levels, monitored with an Active Air Hygro-Thermometer, will help you get the most out of the filter's rated two-year lifespan.