Maxspect Nano Tech Anaerobic Blocks are a new game changing innovation to "complete the nitrogen cycle" and compliment your filtration. Where the original Nano Tech bio blocks and spheres excel in housing aerobic bacteria these patented blocks excel at housing anaerobic bacteria. The denitrification catalyst supplied with the blocks increases the bacteria production within the massive surface area and ideal living conditions on the inside of the blocks.
The Nano-Ceramic beads in the Anaerobic-Blocks are specially treated with our proprietary technology, such that they excel at establishing anaerobic heterotrophic bacteria which strives in anoxic environment.
Two blocks is sufficient for up to 1000 ltr aquariums. 
The catalyst will last for 2 months with refills available to purchase separately in packs of 5.