O2 test kits

[5 Is Not Enough]

I've recently added o2 to my set up.
I'm wondering, how much o2 is enough, and how much is too much?
I was thinking about picking up one of these tetratest kits

They use a color scale to indicate ppm from 2-14.

Anybody have any information on the proper o2 ppm for optimum yeast growth?

 

[SuperiorBrew]

I wonder if it will work in the wort? Dark color and lots of sugars will probably mess it up.

 

[Funkenjaeger]

Generally speaking, homebrewers try to oxygenate as much as possible right before pitching, and then just let it rip. I was told by a representative of Wyeast Labs that the yeast will consume all the available oxygen very quickly. In that case it seems to me that as long as you are not continuing to oxygenate during fermentation I think you're safe. The theoretical maximum concentration you can achieve with pure O2 is something like 42ppm, and so far I've seen no reason to believe that the yeast have any trouble using that right up quickly.

 

[malkore]

from my aquarium keeping knowledge, if i recall correctly, those O2 kits are not very accurate.

 

[5 Is Not Enough]

I was actually thinking about trying it with water. I mainly just want to see if I hit a point of excess o2 or diminishing returns. Right now, I'm using a prototype setup and have no idea how much I should be using. But if I'm shooting for/expecting more than 14 ppm, then I guess this test will be useless.