HydroLogic KDF85 Catalytic Carbon Replacement Filter | Stealth-RO, smallBoy

What the HydroLogic KDF85 Catalytic Carbon Filter Takes Out of Your Feed Water

This is the upgrade cartridge that replaces the standard carbon filter in a Stealth-RO or smallBoy housing, part HGC741622 in HydroLogic's catalogue. KDF85 media and granular activated catalytic carbon share the 10 in body, rated at 1 GPM, working on iron, hydrogen sulfide, chlorine and heavy metals. Well water is where it earns the upgrade. Iron and sulfur are what foul an RO membrane early, and neither has any business reaching a reservoir.

How Long the Stealth-RO and smallBoy Replacement Filter Actually Lasts

Service life splits by which system it feeds: a smallBoy runs far longer between changes than a Stealth-RO does. Sediment still belongs in its own pre-filter ahead of this one, and dissolved salts stay the membrane's job. Growers on chlorinated municipal water notice the change first at the reservoir, where the chlorine smell is gone after the initial flush.

Key Features

• KDF85 and catalytic carbon media: The two media work in series, KDF85 on iron, sulfur and heavy metals, catalytic carbon on chlorine and taste.
• Rated 1 GPM flow: Matches the output of Stealth-RO and smallBoy units, so the cartridge is not the restriction in the line.
• Direct housing fit: Drops into the standard 10 in Stealth-RO or smallBoy housing with no adapter, no tools and no plumbing change.
• 2,000 gal on Stealth-RO, 6,000 gal on smallBoy: HydroLogic's own service figures, measured as purified water on RO and filtered water on a smallBoy.
• Well water duty: Dissolved iron and hydrogen sulfide are the two contaminants that shorten membrane life fastest on private wells.

Technical Specifications