bought a coupe of them few years back
i'm pretty sure they still carry them
http://www.plumbingsupply.com/

this one is the best i heard. still waiting for it on the mail
http://www.petstore.com/ps_ViewItem-...-Dennerle.html

Oh! That's the one I couldn't remember the name of. I got mine from Wendell. I think he had to order it, but anyhow, yes I've got that one, seems to work fine.

What's weird is that unlike other air-line check valves, you can't blow into it and have the air pass. It must operate on some really high pressure or maybe the fact that the gas needs to be CO2 in order to pass. I could not blow into it and I tried as absolutely as hard as I could and got nothing. But put it on my CO2 line and my reactor pH went down, so somehow it's getting where it needs to be.

needle valve
 

That bubble counter/needle valve combo definitely has design flaw. Remove it and replace it with a needle valve from JL's http://www.jlaquatics.com/phpstore/s...ct_ID=cr-pnval

then build a small bubble counter out of acrylic. quite easy to make or buy one retail.

no problem since for me.

hey chin want to make me a bubble counter??
ohh lookie my new needle valve
heres the actual setup i'm using
http://members.shaw.ca/jcaramat/8e_1.jpg

[quote=props]hey chin want to make me a bubble counter?? /quote]

Jesse
i could but why not try buying a barb x female to attach to the end of the old bubble counter?
Then run the tubing (with your fancy dandy check valve on this tubing) from new bubble counter, to the old bubble counter, open the defective needle valve all the way, and just use the bubble counter. IF this doesn't make sense, call me.
chin