ventilation for a hydrohut 3x3

[built2last]

I am running 400w in the new hydrohut 3x3. I have an elf filter with active air 4 in can fan and hydrofarm air cooled hood. The hood is not cooled as of yet but the filter and fan are on 24/7. Fan is sucking air from filter to the outside. Temps are around 78-80 degrees. I am planning on going from the filter >the light> to the fan > out.What should I use for fresh air? I picked up a 60 cfm blower but I think I'll need to take that back. Not big enough. Currently I am using the passive air intakes on the bottom but don't know what to do come 12/12 and I'd like to keep everything on the inside of the tent.

If anyone has a similar setup I would love to take a look.

 

[growMEDS]

My setup is similar. Passive air is all I have

 

[built2last]

what do you do for flowering???

 

[growMEDS]

My tent is always on 12/12 - filter>>air cooled light>>fan>>exhaust. All inside the tent.
My passive intakes are 2 4" holes with vent tubing for blocking light - I don't use the air screen flap things - has good negative pressure (tent is sucking in some)

Take a look through my whole thread and you will pick up a lot of mistakes I made from my first couple setups.

 

[built2last]

Ahhh I see what you mean. Excellent thread man, very impressive. Thanks

 

[FreezerBoy]

What should I use for fresh air?

Two holes each equal in size to the exhaust port. Area of intake should be double the area of exhaust. Avoid intake fans unless you really know your stuff.

 

[built2last]

Thanks guys

 

[built2last]

Another question... I cooled the light by running ducting from the scrubber>light>fan>out the top of the tent. My question is should I seal the light because I noticed I am losing suction in the scrubber or so it seems? The hood is a hydrofarm and has 3 areas to hook the ducting up to. I am using the ports on the ends of the light. Thinking it may be better to go from the scrubber to the side of hood and out the top. Shouldn't I cover up the other port? What about the slight gap between the glass and the hood?

 

[Ipsissimus]

blower fans are design to push air, not pull it. it makes a big difference when approaching static air pressure limits. consider putting your can filter outside the space, to continue passive intake.

 

[growMEDS]

Yes try to seal the reflector.

 

[etinarcadiaego]

Idea

Idea

So I can put my filter on outside of the grow tent after the blower fan, (it'll be the last thing the air hits after leaving my room) and it'll be just as effective as making it the first thing in the grow room the air hits?

I only ask because I am going to be doing this shortly as it is . . .

 

[growMEDS]

I have seen more people say to put the filter on the front of the system so it's sucking not blowing.
Most suggest filter->xxxxx->exhaust->

 

[built2last]

Got it, found what I needed, thanks guys. Growmeds you've been a big help running very similar system but 400. Thanks man

 

[built2last]

from everything I have heard sucking the air through the filter is more efficient than pushing through it. just like growmeds is explaining

 

[etinarcadiaego]

blower fans are design to push air, not pull it. it makes a big difference when approaching static air pressure limits. consider putting your can filter outside the space, to continue passive intake.

Okay, I wanted to be sure cause this guy seems to say the opposite . . .

 

[Ipsissimus]

from everything I have heard sucking the air through the filter is more efficient than pushing through it. just like growmeds is explaining

instead of relying on hearsay, why not rely on research, or just test it yourself? I'm not relying of word of mouth, you shouldn't either. try both configurations, and see whats up for yourself.

just because everyone else is doing it....

 

[etinarcadiaego]

Well it's kind of hard to rely on my research as I have no way of testing a fans actual output versus its rated output or measuring CFM in any method other than "perceived."

I don't have a degree in physics or aerodynamics or fluid mechanics or anything, but I believe the output would remain constant regardless of whether the fan is pushing or pulling and I've found some literature that confirms that, but it's mixed.

Some tests were performed on fans output in auto-related stuff, and the push vs pull appears to depend on other factors.

I just like to post here because maybe someone else has research I can use to make up my mind.

 

[Ipsissimus]

well, research aside, i've tried both configurations, I've found my airflow and odor control were improved with pushing air. I can't find the link but I recall the positive and negative pressures are experienced by different ends of the fan cage, and the shape and slant of blade is optimized to deal with the positive pressure. Notice how the intake is often larger than the output? This eliminates as much negative pressure as possible. That and it's not called a "sucker". J/K

 

[etinarcadiaego]

Right on, thanks man. I think I'll be pushing as well then

What size fan were you running if I may ask?

 

[Ipsissimus]

112 cfm in a closet, when I really noticed. i had an inline carbon filter so it was easy to test both configurations. Sucking was no flow, blowing was little. I've run 465s before and did both configurations without noticing a difference, I think it applies more when approaching the back pressure limit for the fan.