Review on Bluecell 12Pcs Pre Filter Sponge Aquarium by Karen Cooper

These sponges work very well. They are ideal for the Fluval Aquaclear20 HOB inlet filter. I also added an air intake extension to further submerge the air intake in the water. The roughness of these sponges is just right. They help filter the water and create an additional environment for beneficial bacteria to grow. Thus, only one end of the sponge is open. Clean it after the 2nd or 3rd water change. They get 5 stars for performance but only give 4 stars overall because you don't really need 12 of them. Good value for money. How about 5 or 6 for a slightly lower price.