These 2 inch thick reusable sponge pads come in three porosities. Black 15ppi being the most coarse and slowest to clog. The green 30ppi which is less coarse and should be the majority of the sponge used in a filter. The blue pad is 40ppi and is a fine polishing pad and will require frequent cleaning but will remove the most from your water to help get a crystal clear look. All sponge pads can be cut to fit and will even fit the largest filters like the Fluval FX6 and Eheim 1500XL classic and everything smaller. Cut to fit hang on backs or use in sump filters.This foam is not shipped compressed like most sponge pads on the market. This saves you time and saves the pore structure of the foam to give it more longevity. Directions/Specifications Pore Size:Black Sponge Pad: 15ppiGreen Sponge Pad: 30ppiBlue Sponge Pad: 40ppi(different manufacturers rate porosity slightly different as it's an approximation) Pad Size: 11.75 inches by 11.75 inches by 2 inches thick. Cleaning Instructions: Have a bag or container ready to put the sponge in once removed from the filter. Lift the water and sponge out to catch the majority of debris that will come off while removing. Next, use the aquarium water and squeeze out the debris from the sponge. Discard the water and get more water from the aquarium and repeat until sponge filter is mostly free of debris. Reinstall the sponge and wait for a couple hours for the water to clear back up from the debris released when removing and reinstalling. Filter Fitment: All filters (cut to size for best fit)
