gravity

Hello! I have an Excel sheet, where I have a lot of aquarium data, and I have found myself in the need many times to want to know in a direct way how much is in gravity unit the value obtained from a measurement of a Hanna pencil (for example) in ppt. And the other way around too, to have the...

has anyone used any kalkwasser in a gravity fed ago especially this one or should i buy the brs kalkwasser doser