Fan layout for best temperature and airflow....?

Here's a very simple picture to help visualize my options... which would work better? I have a 4" blower, a 6" blower and a 6" booster duct fan to work with, what would you put where and why? I'm using a 400watt digital switchable with a sealed 'Euro hood' with 6" flanges. Growing inside a DR100 (6" port holes). I intend on using the bottom left hand port for intake with one of the fans...

Your advice/input/criticizes' are welcome. thanks in advance... rep waitin' on ya

opt on right with 6in with controller.

jeb5304 said:

opt on right with 6in with controller.

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Why should I suck the air out of the tent through the light hood? Won't this not cool as well since it won't be pulling fresh air?

bump, I've got seeds burning a hole in my pocket, would someone kindly offer their opinion please?

no the one one the left is by far the better option, the only reason id ever go for the one on the right is if i only had money for one fan.
left option gives much better cooling for the light as the one on the right is cooling the light with semi warm air instead of cool air

The duct booster is a piece of junk. It does not produce enough static pressure to be effective.

You always want more exhaust than you want intake so the correct order would be to draw through the filter with the 6" blower and then exhaust that air through the air cooled hood and then outside.

The other fan may not be necessary depending on if you have a passive intake that is big enough.

both setups can be good. the one on the left is good because the air cooling the light never enters the tent. this is beneficial to you because you can remove the heat with out removing the air from the plants. you can run the filter to get rid of the smell, but you dont neccessarily need to constantly exhaust the tent, this means you can supplement with co2. the one on the right, is the more economical and efficient setup, with this setup i would only buy one fan but make sure it is strong enough (like 6" vortex fan or similar). you cant use co2 with this setup, but you will only have to spend money on the one fan instead of two and your electricity will be lower because you are only running one fan. so if you have the money and are interested in co2, then chose the left. if money is tight and you wanna save in the long run, then chose the right. you can control your temps with either one, you just must be sure to get strong enough fans. good luck.

I'm using a similiar system but have two 4" vortex fans....Both are mouted outside the tent....one drawing through a charcoal can-cool tube-ducted to outside. The second fan is drawing fresh air from a crawlspace and blowing through ducts inot the cab and directed toward the cooltube for added temp control. This allows me to really control/adjust the temp by varying the fans speed which typically are set at about 1/3-1/2 speed......

NLXSK1 said:

The duct booster is a piece of junk. It does not produce enough static pressure to be effective.

You always want more exhaust than you want intake so the correct order would be to draw through the filter with the 6" blower and then exhaust that air through the air cooled hood and then outside.

The other fan may not be necessary depending on if you have a passive intake that is big enough.

Click to expand...

Correct, the duct booster is puny, that's why I thought I'd use it as a assist on the passive intake, tents flaps stay down for light concealment so the intake air isn't exactly flowing in...

So you think I should use the tent air instead of fresh air? Why? I guess this is going to come down too, what do you see as the differences between these two setups?

I'd go with the one on the left - I keep mine separate for greater flexibility, for example I can shut off the room vent (say to add CO2 or whatever) w/o affecting the cooltube, let's you use smaller (quieter) fans as well. My carbon filter is on the output side, I have a small fan forcing air on the intake and a larger fan pulling the room air then pushing it through the filter.

ScrogThis said:

I'd go with the one on the left - I keep mine separate for greater flexibility, for example I can shut off the room vent (say to add CO2 or whatever) w/o affecting the cooltube, let's you use smaller (quieter) fans as well. My carbon filter is on the output side, I have a small fan forcing air on the intake and a larger fan pulling the room air then pushing it through the filter.

Click to expand...

The 6" blower arrives tomorrow and I believe I will be going with the dual fan config, (left pic), pulling outside air through my light hood, cooling could be a issue so I'm opting for this method in hopes that I will be able to control temps better.... It will probably take a little tweaking with my timers but I hope I can dial it in to keep things in the optimal range.
Thanks for everyones replies, any other input is allays welcome

just to update, the config on the left has been working great, I ended up installing a speed controller on the fan pulling through the light because it does it's job so well and I'd like to hold onto some of that heat this time of year.... the even bigger heat sucker though is the 170 cfm 4" fan on the filter! I need to get a speed controller for that one especially! If I could turn it down some I could hold onto a great deal more of the heat my light is creating.... this setup is in effect too efficient with my heating needs currently. When things were still hot I was running about 7-8 degrees above ambient temps.