Will my carbon filter last longer if I leave it unhooked until the garden starts to smell?
I filter my air at the intakes of the tent so do I need to install the white prefilter that came with my Phresh 6" x 24" filter?
I would use the prefilter regardless. The choice is yours about when to rub with the filter attached, just be aware that in high humidity around 80% it isn’t super effective. Above 90% and it is more or less useless lol. Also keep in mind that running with the filter can decrease your exhaust cfm by 15-20%.
if you are going to be pulling your exhaust through a light to help cool it you definitely want the pre filter on it