This 450g pack of ceramic media from one of the leading names in aquatic supplies can be added to your aquarium to encourage improved filtration and healthier, cleaner water. This is because healthy bacteria will instinctively settle around ceramic media and help to eliminate toxic waste. In addition, these media rocks will help to anchor and support plants, ornaments, and decorations, as well as improve the appeal of your aquarium.When adding or replacing media in your aquarium, take care to make changes gradually in order to give the healthy bacteria time to colonise to the new media. Adding more media helps to increase the filtration surface area. Replace ceramic media annually for optimal filtration.