Aqua One Filter Pads give the user the ability to cut and shape their pads to suit any filtration system, including Hang on Filters, Canister Filters, Trickle/Mini Reef Systems, Top Filters, Internal Filters, Pond Filters and other Aquarium and Pond filtration systems.The Aqua One CarboPad is a tightly woven chemical filter pad which absorbs residual medications, tannins released from driftwood and dissolved organics. It also supplements any other chemical or biological filter med..