The flow is set to 1. The square footage of my grow space is 224. According to the formula, it really needs about 8 minutes to bring the PPM up to 1500. Problem is, I can't tell if I'm at .5, 1 or 1.5 because the "flow ball" is large enough to span across those gaps.

15 minutes is probably longer then necessary as well.

I really feel like I need a CO2 ppm meter to be absolutely sure, but those things are expensive.

I'm probably just psyching myself out, but it seems like just from 2 days of CO2, my fan leave are huge. I'm approx 5 days into flowering.

thanks