TF-100 CYA test - Correct filling of bottle

[marcgr]

Hi,

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

Thanks,

Marc

 

[JVTrain]

It's not overly critical how much reagent you add to the top. Just as long as it's full up near the top of the label, bottle.

 

[ping]

I've worked around this a couple of ways.

The way I do it now is to add 10ml of water and 10ml of reagent from cylinders to the mixing CYA bottle and shake it for 30 seconds. This way saves a little bit of reagent and I don't need all that much because my pool's CYA is usually 50-80.

The second way that I have used; I marked the mixing CYA bottle with a line that was equal to the 14ml of fluid. The label on my mixing bottle came off after a couple of uses so I just used the label residue as the guide for the line.

All that you are after is an equal amount of test water and reagent mixed together.