This stuff is really green ,in fact they said you could drink it ,not that I would. Its suppose to clean the sensors (which are a problem) we have tried the other methods of sensor cleaning. It also cleans the solids that harden on the sides of your tanks,that rinsing does not get rid of. Like I said he had a good pitch ,but also wanted a good price for it,but you only use a couple of oz.per tank.