for years ive ran 2 ventilation lines. filter/exhaust separate from air cooled lights. ive always blown into filter settin outside the grow space due to filter size. never had any isssues this way . other tan when it came time to routine maintenancece checkin ducting(all rigid) connections and cleaning them, not to mention all the gashes in my hands form the steel ducting. I could go on forever of the madness that comes with my setup due to life situation etc but i'll spare ya'll . lets jsu say I feel like stickin my head in a snaowbank bout now.
bt anyway. the only reason mainly ive maintained two separate vent. lines filter spate from lights is cuz I was leary of the "operating temperature" rating they slap on label on carbon filter boxes sayin max 80 degrees. and heat from bulbs being blown thru filter diminishing its scrubbing potential. but in all my past 5 years or so growing ive never bothered to think of if the rating was C or F til today. its Celsius. meaning max operating temp is dang near 200 deg F.
all this time I would have simply done setup where passive intake, the into light hoods then fan blowing into filter outside the grow all in one strait line. of course everything would be supped up in size for fan/filter to handle the load etc,
but looking back realizing how I coulda made my most dreaded grow chore of all cut in half an then some prolly.
I guess im just foolish to assume that beings I live in America that anything I buy here is labeled according to American standards in measurements etc.. but that just means this has opened a whole new door to me as afr as manipulating my setup to actually improve things an such.
I just wanted to share my experience. im sure theres another person out there who has and or will make a similar play as I have so hopefuly I can spare someone else a future headache.

I am in Canada and in all the years we have had the crappy metric system I still prefer the standard system. Our government thought it would make trading easier with europe.so they tried to make us more european. Guess what I am Canadian not european.

Actually, the metric system is so much easier. I don't know who thought a measurement system based on weird numbers was a good idea, but it is not. If you have a number system based on 10, then your measurement systems should also be based on ten. The American way of measuring things is just and confusing. How many feet in a mile is so much harder than how many meters in a kilometer.....

If everything was in metric it would have been easier but when your number 1 trading partner (USA) uses standard, not so easy, a lot of conversions. 30 years or so later I use both, but I prefer my standard tape measure with inches over centimeters. Although I do have my thermostat set to celcious.

Quote: The Hemp Goddess wrote in post #4

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Actually, the metric system is so much easier. I don't know who thought a measurement system based on weird numbers was a good idea, but it is not. If you have a number system based on 10, then your measurement systems should also be based on ten. The American way of measuring things is just and confusing. How many feet in a mile is so much harder than how many meters in a kilometer.....

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Order one from Canada