Justin Fournier said:
I have used plenty of Red Sea test kits, P04 always worked great. Fe never worked great..... I wonder if it's operator error? Perhaps the color charts were read wrong or something......
I only just now saw your comment, and thought I'd explain why I pooped on the RS kits.
Operator error is always a possiblity with me, lol, but it was not the case with the kits I had, and I've never had trouble detecting color variations. My belief is that the kits where old -- sitting on the shelf for who knows how long -- and one or both of the reagents had expired. I think this is probably not an uncommon problem with certain "hobby" kits. My Hach kits come with dry reagents neatly packaged and premeasured, and an expiry is printed on the packs. They aren't cheap but worth every penny IMHO.