Sizing a VIVOSUN Carbon Filter
The right
VIVOSUN carbon filter pairs to your inline fan by diameter and CFM. Filter diameter must match the fan duct (4, 6, or 8 inch); filter CFM rating must exceed the fan's max draw with at least 15-20 percent overhead. An undersized filter chokes the fan and drops actual airflow at the tent inlet by 40-60 percent of nameplate, which is the most common reason carbon filtration setups fail to scrub odor adequately.
Filter Sizing
RC-48 Coconut-Shell Carbon
VIVOSUN uses Australian RC-48 virgin coconut-shell activated carbon, which is the standard high-grade carbon for grow filtration. RC-48 has a higher iodine adsorption value than recycled or palm-shell carbons, which matters for late-flower terpene loads when odor is heaviest. The pre-filter cloth on the outside catches dust and lint, extending the service life of the activated carbon underneath. Wash the pre-filter cloth every 1-2 months under cold water (no soap); replace the entire filter every 12-18 months under moderate duty cycle, or sooner if you're running flowering tents continuously.
For ventilation and odor scrub setup, see
humidity control.
Related Guides
Pair the filter with a matching
VIVOSUN inline fan. Cross-brand options live in the broader
carbon filters lineup.
Frequently Asked Questions
What size carbon filter for a 4x4 tent?
A 6-inch VIVOSUN carbon filter paired with a 6-inch AeroZesh T6 inline fan is the right size for a 4x4. The filter CFM rating exceeds the fan's max draw, which keeps real-world airflow high enough to scrub odor without back-pressure loss. Pairing a 4-inch filter with a 6-inch fan strangles flow; pairing too large just wastes filter capacity.
How often do I replace the carbon?
12-18 months under continuous moderate-duty use. Replace the entire filter when you notice odor pass-through at full fan speed; this is the most reliable indicator of carbon saturation. Heavy-odor strains and continuous flowering grows can shorten service life to 8-12 months. Storing the filter sealed when not in use extends service life.
Does the pre-filter cloth need washing?
Yes, wash every 1-2 months in cold water (no soap). The pre-filter cloth catches dust and lint that would otherwise saturate the activated carbon prematurely. A clean pre-filter is the single biggest factor in extending the main filter's service life. Air-dry the cloth fully before reinstalling.
Will a VIVOSUN carbon filter fit an AC Infinity duct?
Yes, all 4, 6, and 8-inch carbon filters use standard duct flanges that fit any matching-size inline fan, regardless of brand. The flange is a universal sleeve that takes standard ducting clamps. VIVOSUN and AC Infinity filters and fans cross-fit without adapters.
Is the carbon RC-48 or virgin coconut shell?
Both, technically. RC-48 is the Australian-sourced virgin coconut-shell activated carbon grade VIVOSUN uses. The RC-48 spec refers to the iodine number and mesh size of the activated carbon. It's the same high-grade material used in commercial cannabis filtration, not recycled or palm-shell carbon.
Can I run the filter on the intake side?
Yes, but it's not the standard configuration. Most tents run the carbon filter on the exhaust path so odorous air gets scrubbed before leaving the tent. Intake-side filters are for pulling clean air in from a dusty environment, which is rare in residential setups. For odor control, keep the filter on exhaust.
