Thanks Renee180 - that’s very interesting. I too struggle with reading the color change tests. I’m switching over to Hanna & recently went with the CHEMets Copper Test which is a bit pricey but very readable.Hanna. I realize they do not back this product for salt water, but I had it tested against a $350 photo/digital meter kit that one of the pet stores uses on their tanks and it was spot on with 3 different tank(s)water samples that I had with my Hanna kit. I trust that more than I do trying to use those crazy color charts. My badges now show .05 “alert”, better than the false reading of 1.0 , what a relief!