My CO2 rate of flow = 4.5L/hr

I was curious if anyone else here has measured their rate of CO2 flow in a standard unit of measurement. (ie. Not "bubbles" per second.) Knowing this would allow you to search for a rotameter / flow-meter to use in place of the common & woefully inadequate bubble counter.

It's easy to do. I used a glass measuring cup but a graduated cylinder or any container of a known volume will work. Submerge the cup in a bucket of water and invert. As long as the rim of the glass stays below the surface of the water in the bucket you can raise most of the glass (bottom-up) out of the water and the glass will remain full of water. With your CO2 feed line disconnected from your aquarium put the end of the tube in the bucket so the bubbles flow into the glass displacing the water. Time how long it takes for the glass to fill with CO2 gas & you'll have your measured rate of flow.

 

You do, as in, you do use a flow meter for your CO2? Which brand / model? Do you like it? Does it show adjustments with fine enough resolution to be useful & consistent for returning to a prior setting? (Pics please? )

I just bought these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350326925668
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280519171336

My flow rate should put the bead right in the middle of the scale (physically, not numerically) on those.

I've been looking for one with a nice long but fine scale to show even the smallest adjustments clearly. Till today all I've been able to find are very expensive meters that are borderline-too high of a flow range. 0-1l/h air (or gas, or CO2) just doesn't seem to be a popular industrial flow rate.