Low CFM=High Temp?

Hey I recently purchased 2 of these: http://www.newegg.com/Product/Product.aspx?Item=N82E16811998124

I'm using 2 30 gallon sterlite bins and have the fans set up as 1 intake and one outtake. Currently I only have 3 42w CFLs in the bin and the temps during the day range from 78-86 depending on the time of day. It is indoors, but I only have the AC on during the hottest hours. I of course plan to run more than the 3 CFLs once the plants gets larger, probably a few more 26w. Is 60 CFM enough for my bin or is the heat related to something else.

If 60 CFM isn't enough what would be a good number to shoot for without buying a miniature jet engine? Stealth isn't really that much of an issue, but it is in the same room I sleep in so noise is. At 30 dBA I can barely hear it.

I don't really want to have to have my AC set on 75F 24/7. If it's not the fans what other ways can I keep the temp down? During the night it gets around 65-69F and I crack the window a bit. The temp inside the bin usually drops to 75-77F.

I would perhaps run both fans at the top as exhaust, raise the bins about an inch or 2 off the ground and put passive intakes on the bottom. Another great strategy for rubbermaid boxes is to put them on top of an existing floor A/C vent, esp since we're approaching the summer months.

Just started growing in a bin, what exactly is a passive intake? Also I live in an apartment so all my vents are on the ceiling.

Cloudz2600 said:

Just started growing in a bin, what exactly is a passive intake? Also I live in an apartment so all my vents are on the ceiling.

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means your not forcing air into the tent, box etc. the exhaust fans helps pull air in.

np on your vents ...cool are drops to the floor ...hot rises.

use both fans for exhaust. a passive intake is just that. an intake w/o a fan. do 2 intakes that are slighly larger than the fans are.

This is what I'm working with now, so should I just cut a hole below the top fan and take the intake fan below and make it my second outtake and leave the hole(maybe widen it?) alone?
I saw a diagram that has the outtakes on opposite ends, not sure if the cables are long enough for that though.

The top holes on the second picture are where I feed the cables for my lights.

the passive intake should be on the opposite side of the box than the exhaust. i'd duct take over your current intake spot and make 2 new ones on the other side.

Couldn't I just flip the bottom bin around and add another hole above it or is there some advantage to having the holes side by side? Trying to do the least amount of work possible. I had more issues than I thought getting the stupid bin to cut, what do you recommend to cut it? I used a knife.

yeah. i suppose just filpping it around could work for one of the holes. as for cutting...what do you have on hand? serrated works alot better in my experience than if your not using one that is serrated currently. i used a hacksaw before after getting the initial cut going and its pretty quick, so if youve got something like that it would be even better.cutting holes is a pain but you got to do what you got to do..

Yea I have a serrated, I tried with a non-serrated and saw that it wasn't going to work right away. No hacksaw.

a good way to cut plastic is with a regular non serrated knife and heat it up with a propane torch or jet lighter or maybe something else would work just get the knife blade hot enough to soften the plastic as you cut it.

how many cubic feet is that bin btw? you want the air in the room to be totally replaced at least once a minute and with using larger cfls as you add more you'll find it becomes even more important that you have a quick air replacement rate. i always tried to get at least 2 times a minute on my larger cfl grows. honestly the more i think of it the more i think you should get something a bit stronger than what youve got. it would be alot easier and more effecient to have just 1 strong exhaust fan with the passive intakes, you could always use the computer fans for blowing on the plants inside the grow area. i have used cfls in the 40w range in the past alot, i had a scrog dresser going with 24 of them for quite a while but ive also had plenty of smaller grow boxes and areas using the larger cfls and i dont think you'll be able to do more than 5 or 6 in that area with what you have for ventilation. summer is going to make it even more difficult and if you want to run them during the day you'll probably need to have the ac going even with a stronger exhaust fan if the ambient temp of the room the grow bin is located in doesnt stay pretty cool. like in the low to mid 80's tops. that still might not be enough to stop the cfls from pushing the temp up over the low 90's range. an option to consider is adding more smaller bulbs that you can place closer to the plant when you increase the lighting like you said you plan to do, it also helps you maximize your space as you can get the plant within 1/2 inch of a 26w usually if youve got a circulation fan blowing between the lights and plants while it cant get much closer than 2 1/2-3 with a 40w. it might nor sound like a big deal but you'd be surprised how quickly you run out of room. you can also use the 26w wherever you need a bit of extra light to help fatten up colas and really surround your plants with light on all angles and can really fatten up your nugs substantially. i no longer use the 40w bulbs myself for the reasons listed. its something to keep in mind. lol

Box-cutter/razor blade

Yea, I bought a 6 pack of GE 26w 2700k CFLs awhile ago. I guess I need to buy some 6500k. If you say I need a more powerful fan can you link me one of give me a CFM rating I need to look for? Ambient temps outside the bin tend to be 75-80F during the day. I have my lights off from 3pm-7pm to help with the heat since it's the hottest hours of the day. I'm actually only trying to do 2 plants per cycle just for personal use.

When you say use the PC fans for blowing the plants inside do you mean take them out of their respective holes and just stick them inside the box? I've got enough sockets to run 6 lights. I thought about getting a fan for the inside of the bin. Should the fans be hitting the lights or just barely hit the top of the plant(which will probably hit the lights anyway)? Yea, I used a box cutter to get started on the exhaust fan, this plastic is just so damned hard that it's hard keep the blade cutting in a straight line.

+rep for everyone who has helped(which is everyone ^_^)

Oh I'm really not sure how many cubic feet, the bin says it's a 30 gallon or 114 liter and its a sterlite brand.