Struggling with low pH? Frustrated by slow coral growth? The IceCap Color Changing CO2 Absorbent Media is a solution. This IceCap CO2 Absorbent Media must be used with a CO2 Scrubber, such as the IceCap CO2 Scrubber (it also requires a protein skimmer). The way it works is simple: you just attach the tubing that comes with the scrubber to the air intake on your skimmer. Then, you connect the other end to the CO2 scrubber and you're done. That's it! Now you'll be able to raise the pH of your aquarium and control carbon dioxide. When the media turns pink, then it's time to replace the media. Or, if your pH drops, it's time to replace the media. 1 kg. Precise mixture of Calcium hydroxide (Ca(OH)₂) and Sodium Hydroxide (NaOH). Turns pink when used up. Perfectly pelletized size for minimal dust and maximum performance. NOTE: You must have a CO2 scrubber and protein skimmer to use this products.