Thanks Bill I hope you and your brother are doing better these days.

CO² uses an oxygen regulator from what I know but I don't think the regulator knows any better. You do need the electric valve to turn the gas flow on and off. The only dangerous part of using CO² is when the level rises above 1000 ppm for extended periods of time. You really want to get it up to 1500-1800 ppm and hold it there for hours at a time. That is the dangerous part you can't enter the room while you are using CO². It can make you pass out and kill you but it does take well over 2500 ppm to do that. I just don't take any chances so 30 min after the lights go on I start the CO².

Now here is where others freak out.

I do my work during the dark period under 25w green bulbs (plants donâ??t see the color green) so it safe to enter and not waist the CO² the plants need. You do need to exhaust the CO² from the room once the lights are out plants canâ??t process the CO² during the dark period or if you have then under fluorescent lights.