Want to know how to raise pH in reef tank? Corals are highly sensitive to pH. Connect a CO2 scrubber, a CO2 absorption filter, to your protein skimmer to raise reef tank pH. It is important to maintain a high reef tank pH level. For many setups, especially in the winter with windows shut and heater on, aquarium pH levels drop due to higher CO2 in the air. Use a CO2 scrubber instead of pH buffer for an elegant solution. Create a CO2 scrubber with a Phosban reactor or another media reactor. Fill the CO2 scrubber with a CO2 absorbtion media, like Two Little Fishies CDX media. Use a CDX adaptor to connect the protein skimmer airline to the reactor. As the skimmer draws air through the scrubber, CO2 is removed, which raises tank pH. A CO2 scrubber reef aquarium system is the best way to raise pH in reef tank, often raising pH from 7.9 to 8.3. Replace the CO2 scrubber media as needed, about every 2 months.