Has anyone out there ever heard of a product called "cleanwater"? It is marketed in the US by Penn-Plax, but is made by a company in the Netherlands by the name of "C.R. Products". It claims to remove the following: Phosphate = 3.5 g/kg of cleanwater Nitrate = 13 g/kg of cleanwater Nitrite = 10 g/kg of cleanwater It also states that it will keep your tank clean for up to 3 months. Thank you for your help.