Hygger aquarium bio media provides both mechanical and biological filtration for your aquarium/pond. It’s porous structure acts as mechanical filtration to catch particles as well as providing a surface area. It is a great aquarium ceramic media that serving dual purpose to cover chemical and biological filtration you need for clear, sparkling water that will allow your fish and plant life to thrive. <br><br> Features: <br> Improves Water Quality and Clarity<br> It is reusable, just rinse them occasionally and put back in tank<br> Application: aquariums, sumps, filters, aquaculture and ponds. <br><br> Specification: <br> Material: ceramic<br> Each dimension: 6.2" L× 1.5" Dia <br> Weight: 90 grams/each. 40-pack: 7.9 lbs; 80-pack: 15.8 lbs<br><br> Note: <br> 1. These bio medias are so fragile that we can't guarantee there is no cracks or breaks in transit. Nice packing will be applied to protect media blocks. Even if it cracks, it will not influence the effectiveness of the media. <br> 2. Rinse these bio blocks thoroughly before use. Please remember to rinse them in aquarium water not tap water. <br> 3. Replenish only ⅓ at one time to allow proper seeding. <br> 4. It usually takes 2-4 weeks for good stuff to grow. Thus, we recommend to replace partial media filters every 3 months. <br> 5. It is better to place filter pads on top to filter out debris. This will prolong the service life of aquarium media. <br>"