I pulled out my (brand new!) Bluelab Truncheon and looked on it to see what you're talking about and mine goes to 60 on the CF scale! I haven't any idea, by the way, what CF stands for!

I grow lettuce and leafy stuff mostly and use an EC of 1.8 with a pH of 6.3. A reading of 1.8 EC corresponds to 16-to-20 on the CF scale.

I grow tomatoes and use an EC of 2.5, which corresponds to a 24-to-28 CF reading, keeping the same 6.3 pH as with the lettuce if it's any help.

Both the green leafy stuff as well as the tomatoes seem to be loving life, so I guess I must be doing something right.

My water, by the way, is so hard you can almost walk on it! Hope this helps.

Looks like you got the Commercial version. I should have done my research and shelled out the cash. My version goes from 0 -36 cf. I guess anything much above that must be for intense greenhouse operations. Thanks for your help.

Mine measures up to 3.6 EC, which is 36 CF since CF is just EC x 10. I personally wish the other values were just dropped since EC is the only thing measured. I grow very tasty tomatoes. I don't see why you would need higher than 3.6 despite the charts. I usually use quite a bit less, really. I tend to go by an EC of 2.0 to 2.6 and seem to do just fine. You didn't buy the wrong truncheon so pack that buyers remorse away and start feeling better. You got a great product there.