Brightwell Aquatics Xport-BIO Biological Filter Blocks, 1.5 in, 4 Pack

Brightwell Xport-BIO blocks give bacteria a large surface area to grow, helping reduce excess nutrients such as nitrate and phosphate. They work alone or beside other media in aquariums and ponds.

• Size: 1.5 in blocks, 4 pack
• For marine and hard freshwater with a pH of 7.5 or higher
• One 1.5 in block suits 20 to 40 gallons
• Provides anaerobic area for nitrate conversion to nitrogen gas

Rinse the block in aquarium water and seed it with your bacteria product before use.