EcoBio-Stone Nanos are volcanic rock and cement containing 100% pure beneficial bacteria spores, which effectively clarify cloudy water in aquariums, reducing maintenance. Simply rinse off the EcoBio-Stone, soak overnight and place in nano aquarium. Using natures system of purifying water, EcoBio-Stones beneficial bacteria break down organic waste into ammonia, then into nitrites and then into nitrates, which are processed by vegetation or by anaerobic bacteria changing the nitrates into nitrogen gas, which dissipate into the air. The process of building sufficient amounts of beneficial bacteria to take care of the conditions in the average tank, normally results in crystal clear water in 2 to 4 weeks. EcoBio-Stone Nano safely purifies water, eliminates odors and creates a clear and clean environment for fish and other aquatic life just as in nature. EcoBio-Stones volcanic stone also leaches back the essential calcium and trace minerals, which are normally returned to water with frequent water changes. Note: if the water in your tank is very acidic it is best to acclimate your fish to pH neutral water by doing water changes before adding EcoBio-Stone Nanos.