ONEdersave Products’ EcoBio-Stone Nano uses unique beneficial bacteria spore colonies in volcanic rock to speed up the nitrogen cycle and keep aquarium water clear and clean, just as in nature. The perfect size for a betta tank, the product treats from 0.8 to 1.5 gal. EcoBio-Stone Nano 2-pack will treat from 1.5 to 3 gal. of water. The product works in both freshwater and saltwater tanks for about one year. It eliminates odor and reduces the need for maintenance by frequently replenishing beneficial bacteria, which breaks down organic waste into safer byproducts.