Here is the pic Lan sent me.
View attachment 20462
. But I did run CO2 on planted tanks and have built a few DIY regulators for dosing in that hobby...accuracy is critical either way. Just food for thought, but if you are adding a bubble counter and solenoid, it may be worthwhile looking into a new needle valve. I should also mention...looking at that picture, I honestly don't see that the needle valve you have would allow you to hook up the bubble counter and solenoid...but I could be wrong. It's hard to tell from the pic: I don't know if the end that the CO2 tubing is connected to is a standard 1/8" male thread that you would be able to add a bubble counter and solenoid to inline...or if that is only threaded for the compression fitting.