Aeration stone mixup

How can I tell the difference between the 2 micron stone and the .5 micron stone. I have both and did not realize that the sizes were not stamped on them anywhere. I put them in a drawer side by side and don’t know which is which. I don’t want to use the wrong stone with the wrong aeration setup. Thought about hooking them up and seeing if there is a visible difference in some water. Any thoughts?

I think comparing bubble sizes would tell you, also the relative flow rate of the smaller stone will be lower.

I would think if you put them both on equal lengths of tubing and then used your mouth to attempt to pull water into and up through the tubing while the aeration stones were submerged in water that you would notice a big difference in the ease with which one let water pass through. The 2 micron is very difficult to do this too, so I would think the .5 micron would be almost impossible. Try it and tell me if this helps you distinguish between the two, cuz now I am curious.