CANNA FLUSH is a product to clean substrates and plants from any excess nutrients. This is necessary, because excess nutrients can have a bad influence your next growth cycle. They could lead to over-fertilisation or malnutrition, for example. When used just before harvest it makes sure the plant gets rid of all excess, which will lead to a clean and tasteful harvest. CANNA FLUSH effectively cleans the substrate without killing any useful bacteria or benecial fungi, as can be the case when you use reverse osmosis or de-mineralised water.