Lee's Large Bio-Pin Balls are a state-of-the-art biological filter media designed to maximize the efficiency of your freshwater or saltwater wet/dry filtration system. These specially engineered balls provide an immense surface area for the colonization of beneficial nitrifying bacteria, which are essential for breaking down harmful ammonia and nitrite. By promoting a healthy biological filter, Bio-Pin Balls help maintain stable, crystal-clear water conditions for your aquatic inhabitants. Each large Bio-Pin Ball features a 1.60-inch diameter and is covered with 150 individual pins, or drip points, which create turbulence and dramatically increase the available surface area to approximately 130 square feet per cubic foot of media. This design also creates significant void space between the balls, promoting excellent gas exchange by allowing oxygen to easily reach the bacteria and facilitating the off-gassing of carbon dioxide. The balls can be interlocked for structured placement or used randomly within your filter sump or chamber. This bulk 2500-count package is ideal for aquarists setting up large aquarium systems, upgrading existing filtration, or for professional maintenance services. It provides enough media (33.78 gallons) to support very large bioloads. For optimal performance, it is recommended to use one gallon of Bio-Pin Balls for every 20 gallons of saltwater or every 35 gallons of freshwater. This ensures your wet/dry filter has ample capacity to handle biological waste and keep your aquarium ecosystem healthy and thriving.