The <b>N – Type SCD Probiotics ceramics</b> is used to absorb and eliminate ammonia nitrogen. What does this mean? N-Type ceramics will take the nitrogen out of the water, thusly breaking down the water molecules to increase the amount of oxygen. It can be used in tap water, sprinkled in the bottom of a litter box, bathtubs, fish tanks, plant water, and in flower vases. N-type ceramics will last a year.