Correct me if I'm wrong. I have a Hanna which I use but hate to mess washing the vials all the time. Have a old lovi bond so thought I would just buy a new disk. Wrong. They changed the size of the vial you view thru so it would not be accurate. I still use my old one with this in mind. Golden and light didn't change so it would work to grade that category. All of med. falls into amber and all of grade b falls into dark robust. So only what grades grade a dark amber do I need to use the Hanna to see what way it goes, Amber or dark.