The pH in a reef tank should be around 8.3 for optimal coral growth. If you"™re struggling to maintain pH, or if your aquarium suffers from chronically low pH, connecting an IceCap CO2 Scrubber to the air intake of your protein skimmer is a great way to increase and keep your pH level within ideal ranges. The IceCap Color Changing CO2 Absorbent Media is included.