Thank you for viewing! This product uses bacteria that break down waste, leftover food, and gravel debris, keeping the water clear and clean. Simply add it, and the bacteria will remain active for a year. This is a set of 3, and individual sales are not available. Although it is a new, unused item, please refrain from purchasing if you are looking for a perfect product or are particularly concerned about its condition, as it has been handled by a person. Thank you for your understanding. I also have other turtle-related products for sale.