Self-Adhesive Monotub Filters 65 mm | 12 pieces

Walk into any active monotub-tek community and the 65 mm Self-Adhesive Monotub Filter is the default. It is sized perfectly for the FAE holes drilled into 30–60 L Sterilite, IRIS or similar storage tubs — the size range that virtually all serious monotub growers use. With twelve patches per pack you can build (or rebuild) two full tubs with a layout of 4–6 filters per tub, which is the sweet spot for fruiting most cubensis varieties.

The reason this size is the default? FAE math. A 65 mm filter has roughly 33 cm² of filter surface. Four of them give you ~133 cm² of total exchange area, which keeps CO₂ levels comfortably under 1000 ppm in a 40 L tub with normal mushroom transpiration — without needing a fan. Smaller filters force you to drill more holes; larger filters create localised CO₂ dumps. 65 mm hits the optimum.

Also available in: 38 mm | 90 mm

Standard 6-filter layout

Drill three 50 mm holes with a hole-saw per long side: two high (for CO₂ venting) and one low (fresh-air intake). Skip the short sides. This creates a passive convection loop that pulls fresh air in low and pushes humid CO₂-laden air out the top. Wipe each hole's perimeter with 70% IPA, peel, press firmly for 30 seconds.

Specifications

Best for

Standard monotub tek setups (Sterilite 50/60 qt, IRIS 41 L, RUB 50 L), serious home growers, follow-along tutorials.