First you not your plant, safety is first and you have no regulation. Which should be about 1500 ppm to maximize the co2 along with higher temps, so the plant will suck it up.
DEATH OF CO2 , if you do not know what your putting and have a leak, you have a death trap.
Rule never chase a dead man, alway vent the room before going in.
C20 falls like a rock so you must move air upwards.
The reason people pay $1200 for a controler is its worth it.