My high school chemistry teacher always taught that when reading the fluid level in a piece of lab equipment, to read from the bottom of the meniscus of the fluid. That works great for the graduated cylinders in the TF-100, but when it comes to the mixing bottle for CYA, when adding reagent to the top of the label, by the time the bottom of the meniscus is at the top of the label, the top of the meniscus is way up into the conical part of the bottle. Is that correct? it looks weird.
I can take pictures if nobody knows what I am talking about. This shows how to read lab equipment correctly: Meniscus - Wikipedia, the free encyclopedia