Two Little Fishies CDX Carbon Dioxide Adsorption Media is an essential water-chemistry management tool engineered to elevate and stabilize aquarium pH levels, particularly in enclosed indoor environments with elevated ambient CO2. Designed to be housed in a media reactor (such as a Phosban Reactor) or CO2 scrubber connected directly to the air intake of a protein skimmer, CDX strips carbon dioxide from incoming air before it dissolves into the water column as carbonic acid. By continuously drawing CO2 out of the system, it boosts calcification rates in stony corals, suppresses nuisance microalgae growth, and ensures a stable pH baseline. The premium-grade granules feature a built-in color indicator that shifts from white to pink as the media becomes exhausted, clearly signaling when replacement is needed.
