So I was recently going to buy an LED but I decided that it's overpriced and it's cheaper to do an HID grow and Ill probably even get a better yeild. Anyways my problem is I really can only put together a passive air intake for ventilation. The grow tent/or box is in a cooled basement. The bestI could do is hook up a carbon filter and a 4 inch inline exhaust fan (no i will not go up to 6) which would lead ducting out the window. I am thinking that I can avoid this by just going with a 250 MH/HPS so I don't need any ventilation I can just use a CO2 Enricher and sticking a fan in the tent.
4 inch filter, fan, and fucting won't be much cheaper than 6 inch. You'll want to exhaust the heat and bring in new CO2 as well, using some cheap CO2 enrichment won't solve everything. Doing CO2 properly would actually cost a lot more than just having a proper ventilation set up. The more you skimp up front, the less you'll have in the end. A 400 watt is definitely going to yield more than a 250 watt, and also cost nearly the same to setup. All in all a passive intake is fine and actually preferred. Just as long as you have an active exhaust.
The reason I am going with 4 in" is because I want to keep it as condensed and stealthily as possible. I will have an active exhaust but is the passive intake okay in my dusty unfinished basement? I tried sweeping and stuff but its just sooo dusty.
Ok I was just checking to see if it was purely from a price perspective. I'm sure you can look on here about making passive intakes able to filter as well. It's done with normal HVAC, I bet a new filter cut and taped in place over the vent would be easy enough to maintain and cheap too.
Yeah I would say so. Let's say for simplicity you have one passive intake near the bottom. The rest of the tent/box is sealed nicely. The exhaust fan should be creating a negative pressure in the tent. The air will still want to come through that passive slot with a filter on it, they're breathable. Once it starts clogging you can just swap in a new one. I did a general search of "HVAC filters" and got this as a first result http://www.amazon.com/Filtrete-Living-Filter-1-Inches-6-Pack/dp/B002CJN0H2/ref=lp_13399891_1_3?s=hi&ie=UTF8&qid=1432427454&sr=1-3 and even cutting those filters in half would give you 12 total, 3 months each... 36 months for $30. I'm sure there are 1 packs out there, other options, variables in their actual effective life span... but I'd do it just for the low cost alone in a dusty basement.
Awesome man you literally saved me looking all over the internet . I am gonna start a grow journal pretty soon here. Id love to have your input eventually
Awesome! Glad to have helped. A journal on here is a great idea. I'll sub up when you get it going, just post back here so I can see the link. Also there are so many others on here with lots of good knowledge. It's hard to go wrong on Grasscity!