CO2 use should be when the lights are on, that is when the plants use it. I heard that co2 should only be used during the growth stage. I am currently useing it in flowering and it definately has increased the size and growth rate of buds. i won't know about potency effect untill i test this batch.
i keep the co2 at 1500 ppm.
the grow room must be air tight or you're just wasting the co2
also a small fan on the floor pointed upwards keeps the heaver co2 dispersed well.
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