Self-Adhesive Monotub Filters 90 mm | 8 pieces

The 90 mm Self-Adhesive Monotub Filter is built for setups that have outgrown the standard hobbyist scale. If you're running a 60+ litre bulk monotub, a multi-tray martha tent, or you have a small inline fan or ultrasonic humidifier pushing air through a sealed grow chamber, this is the patch you want.

The other reason growers buy this size is ducting. Drill a 25 mm hole, stick a 90 mm patch over it, then push a humidifier hose or short length of 25 mm PVC pipe through the filter media. The synthetic nonwoven self-seals around the hose and you have an instant filtered cable-gland for moist air injection — no silicone, no grommets. The same trick works for low-voltage temperature/humidity sensor cables.

Also available in: 38 mm | 65 mm

When to choose 90 mm over 65 mm

• Your tub is 60 L or larger
• You want fewer holes to drill (2 large vs. 6 medium)
• You plan to duct a humidifier or extractor through the filter
• You are running an actively-fanned chamber and need higher total CFM

Surface area & airflow

One 90 mm patch ≈ 63 cm² of filter area — roughly equivalent to two 65 mm patches stacked. Two of these on opposing sides of a 60 L bulk tub provide passive FAE comparable to six 65 mm patches on a standard tub, with much cleaner aesthetics.

Specifications

• Diameter: 90 mm (3.5")
• Filter media: 0.22 micron polypropylene nonwoven
• Adhesive: pre-applied, autoclavable, water-resistant
• Pack contents: 8 patches

Best for

Bulk monotub grows, martha tents, fan-driven fruiting chambers, ducted humidifier setups, commercial-scale home grows.