Quick ?

In my veg room is it o.k if i run the exhuast fan and oscillating fan just when the light is on if temp is o.k?
in the flowering room is it o.k to run the exhuast fan hooked up to a scrubber and oscillating fan when the lights are on?
the intake is just a duct from the crawl no fan
if not why?

no help?????

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