Airbox Refill Cartridge 4 Filter Size:Airbox Refill Cartridge 4 Plus The Under Current utilizes negative

The Under Current utilizes negative water pressure to recirculate oxygenated nutrient solution through the plant's root zone ensuring pH and EC levels are uniform throughout the entire system

Avoid excessive water volume

NOTE: liquid CO2 tank not included

and works with heavy gauge ABS grow mod trays that will not bow

calcium and iron

Airbox Refill Cartridge 4 Filter Size:Airbox Refill Cartridge 4 Plus The Under Current utilizes negativeRefill cartridge for Air Box Air Filter Stealth 1 2 3 4 4+, fits these three models. Single Filter. This refill cartridge size is suitable for Airbox 1, Airbox 2 and Airbox 3, Airbox 4, and Airbox 4+. (IMPORTANT: Order 1 OR 2 OR 3 OR 4 OR 4 Plus cartridges as required for your Air Box unit)