Originating in Japan, Ultum Nature Systems Controsoil consists of high-quality natural soil and volcanic ash. It’s common for competing substrates to cause ammonia levels to spike. While this helps “jump start” a tank and promotes plant growth; it is toxic to livestock and can cause unsightly algae during the initial stages of an aquarium setup. Controsoil provides the perfect level of nutrients without excess. Many have successfully added livestock within the first 24 hours of a newly set up tank with this substrate without worry. We do however suggest making sure that ammonia and nitrites are eliminated before adding livestock.