The AquaClear AC70/110 Clear-Carb Insert Value combines the benefits of Carbon and Clearmax for fresh and saltwater aquariums. It eliminates odors, discolorations and impurities, while controlling phosphate, nitrite and nitrate to produce crystal clear water. For the AquaClear AC70 Power Filter and AquaClear AC110 Power Filter. The Product Manual recommends you replace the Clear-Carb Inserts every month. 2-pack.