Quick newbie question… Once I figure out how to program this Vivosun timer, should I use it on both the lights and ventilation? I read somewhere here or there, that you don’t have to run your exhaust fan when the lights are off.
TIA
Dys
I never heard that 
if you have a controller with your inline fan i have heard setting the humidity temp and or temp turning the inline fan off. Otherwise you have no control over the humidity: may work in Veg but i wouldn’t do it in Flower imo 
I hadn’t thought that through. I guess I was thinking about CO2 retention or something but that goes against the idea too since CO2 is associated with photosynthesis (ergo ‘lights on’).
Thank you for the advise.
Dys
Yes crank it up u need no stagnate air want that fresh air
I understood you wanted co2 which the plant turns to oxygen… You want to get rid of the oxygen. I’ve se lots of people with co2 tanks in their grow…?
Watched a vlog by Highigan and they pretty much cemented my attitude that (for small growers) adding CO2 is a big WOMBAT (Navy speak for waste of money brains and time).
3 Likes
Pends on how u run ya grow sealed or useing air
I use positive pressure and it’s all about that fresh clean air some people have sealed set ups only way id introduce it unless u just dumping it out ya vent but ya seal the grow and O2 temp u can get dencer buds ahh but I can wit fresh air sooo it’s just gotta dial ya grow 