I don't think fan power (CFMs) are a linear relationship. I think they follow a logarithmic relationship. Double check me on that but 50% power of a 420CFM fan, will be quite a bit lower than 200 CFM. But double check that.
Okay okay cool thanks for your feedback. I figured. I was assuming turning down the fan to 50% power would roughly be around 200cfm, give or take. Or close to it
What else is in your room putting off heat? Your math is right. I think most people get a little bigger than what they need to account for ballast, water chillers, etc also puttin off heat in the room. 315s won’t put off much heat on their own.
Wall fans, dehuey, maybe a C02 burner(need to research as have seen people have trouble with some fumes or something). I was just hoping someone had a figure like they do per De hps figure. For instance I hear that if you figure 6k btu per 1k that leaves enough extra room to cool C02 burner and dehuey. I was really hoping that a 12k mini split would do the job for 8 x 315 but now I’m not sure. Was hoping someone would chime in that had experience in cooling multiples with a mini split. My math right now say 315x8= 2520 watts x 3.41btu =8593 btu. By that theory a 9k btu would cool the lights and I’m sure that is wrong.
I’d get a 12-15k btu unit personally. Just to have the extra cooling power. Probably lean towards 15k so that way it’s not working close to max power to Cool the room with 8 lights, ballasts, fans, dehu, C02, etc. If anyone else has any input feel free to chime in. But I think you’ll be fine.
I have to jump in on this conversation cuz I love a good old comparison of lights. I've done light setups in all kinds of ways. My new setup combines the hortilux 600 ballast that runs those new ceramic hps lights with a cmh 315 under a big ass hood(28"x34") and then I surrounded the hood with led cob lights. Talk about missing no light spectrum. And in veg I just use the metal halide blue daylight bulb instead of the ceramic hps which is for flower.
Looks like 110v model...
You really need a bigger tent (3'x3'x6.5') and exhaust fan (6"). With only a 5' ceiling you'll have to sacrifice veg time, and therefore yield, by flowering early to control plant size (even if you do LST).
