You may be able to find a welding/cutting regulator and flowmeter combo, but the flow rate will likely be too high. You need more when using it as a shielding gas. The upside is, you may find one with a direct read scale for CO2 as well as mixed gasses.

If you do find just a reg, make sure the output ranges are within the operational limits of the solenoid and flowmeter (20-60psi is perfect). You don't really need more than 10psi on the output. You'll get more flow than you need...in fact, 10psi will max out your flow meter if you crank it up.

The combo I mentioned is around $70. Not bad considering it includes a solenoid that sells for around $30 online (and the other stuff you'll probably throw out).
TestPilot Reviewed by TestPilot on . CO2 so what the simplest and cheapest way to provide co2 for a growroom?i expect the air around here is 500 to 600 ppm since i am right on a busy main road near a town centre in a city...last time i tested a different grow room in flower i still got a decent 400 ppm and all that was exhausting i ntheir was a decent sized air pump getting rid of air into the attic and it was only a small room packed full of blueberry.... what about this sugar/yeast/water idea? what about burning candles in the Rating: 5