Question on pushing air through carbon filter outside of tent

[NugHeuser]

I'm kind of strapped on room inside the 8x4 tent plus I lost the bracket to hang the fan and don't trust the the hanging carbon filter to support the fan as they're already a fairly loose fit. I don't want it on the floor of the tent because that's taking up area where plants could be, plus one of my cob lights would be in the way, so that's not an option.
That leaves me with keeping it outside of the tent and pushing air through the carbon filter outside of the tent. I've heard this hurts on the efficiency of air flow, I'm hoping someone can fill me in on if that would be the case. It is an 8" fan and filter, will that still be sufficient enough for a scrog 8x4? Or do I need to go up to 10"?
It would really be nice if I didn't have to go up to 10 inch.
Appreciate any feedback.

 

[zypheruk]

It works perfectly fine, just take the dust filter that comes with the carbon filter and attach it inside the the cf rather than outsides. Works 100%

 

[NugHeuser]

It works perfectly fine, just take the dust filter that comes with the carbon filter and attach it inside the the cf rather than outsides. Works 100%

Cool, so in your opinion an 8" fan and filter are fine for this space?

 

[zypheruk]

It really depends on what your fan can push/pull to be honest. Try it and see, if you find it isn't then you can either go up in fan size are run two and enjoy the extra confidence that your filter is doing a better job filtering the smell, that would be a route with considering.

 

[Rakin]

I’ve done it and it works. You still want to prefilter before the carbon

 

[nevergoodenuf]

For no chance of smell leaking out, directly attach fan to filter. That way all ducting is negative pressure. If it is a duct booster fan, then no it won't work.

 

[Bakersfield]

I've done both in and out with the fan and it works either way.

 

[NugHeuser]

Well I have it all hooked up, C.F. on an 8" inline(720 cfm), hooked to 4' of straight ducting to a 90 degree fitting into the tent with the a cut portion of the c.f. pre filter taped over the exhaust port. The bad news, I have what seems to be zero negative pressure with all vents closed.. The carbon filter only has about 4 months use out of it but I don't think I had the pre filter around it when I used it before but I'm not certain.
I also don't feel any bit of air movement coming from the outside of the carbon filter whatsoever.
Do you think my c.f. could be plugged up already?

Edit: Prepare to laugh your ass off. I had the fan on backwards, and a couple large duct ports on the top were open.
After that I now have neg pressure, was starting to think I needed a new c.f. or to go up in size of fan and filter.

Just got the tent yesterday and still setting it up. Will be running 3 3500k 90 cri 3 cob rails along with 2 philips 315w cmh's.

 

[NugHeuser]

Its a bit messy, just beginning to get this new setup going. Eventually it'll be all scrogged out is the plan with a seperate 5x5 for veg.

 

[coreywebster]

I'm still struggling to figure why you couldn't set it all up internally but hey whatever works for you man.
I am literally laughing my arse off about the backward fan though!
Be good to see it all scrogged out and running with the cob cmh combo.

 

[NugHeuser]

I'm still struggling to figure why you couldn't set it all up internally but hey whatever works for you man.
I am literally laughing my arse off about the backward fan though!
Be good to see it all scrogged out and running with the cob cmh combo.

Just because it was easier to set up outside the tent since I already had all my lights up and everything, plus there's not much room to work with as far as hanging it goes, with all the lights hung everywhere. The only place it could be hung it Would've been along the width of the tent in the middle of the tent and pre measuring things out with the 90 degree elbow was cutting it close to even fitting in.
But yeah I'm pretty excited as well. I have some gg#4 s1's, purple punch s1's and agent orange bag seed in there now, along with a few randoms.

 

[coreywebster]

But yeah I'm pretty excited as well. I have some gg#4 s1's, purple punch s1's and agent orange bag seed in there now, along with a few randoms.

Ooo nice selection man, very nice indeed

 

[NugHeuser]

So the negative pressure in my tent, even with all vents closed, has become almost unnoticeble, the fan still blows hard though when you detach it to check air flow (8" vivosun inline, so I'm wondering, is an 8" inline going to be sufficient enough for this 8x4 scrogged out? It scares me without seeing serious negative pressure in that tent because odor control is extremely important.
Does this sound typical for an 8" fan to have prolems sucking the sides of the tent in? Maybe the carbon filter has clogged up? Or should I go up to 10"?

 

[Rakin]

So the negative pressure in my tent, even with all vents closed, has become almost unnoticeble, the fan still blows hard though when you detach it to check air flow (8" vivosun inline, so I'm wondering, is an 8" inline going to be sufficient enough for this 8x4 scrogged out? It scares me without seeing serious negative pressure in that tent because odor control is extremely important.
Does this sound typical for an 8" fan to have prolems sucking the sides of the tent in? Maybe the carbon filter has clogged up? Or should I go up to 10"?

I’ve never used a tent so I can’t answer for that. What size of filter do you have? And how is the pre filter set up? Could be the prefilter being triple layered inside the carbon filter could be your problem. Could be clogged. If you have an 8” filter I would go up in filter size before fan size if you can’t get it hashed out. Also I would not use flex duct and make the duckt as short as possible.

 

[NugHeuser]

I’ve never used a tent so I can’t answer for that. What size of filter do you have? And how is the pre filter set up? Could be the prefilter being triple layered inside the carbon filter could be your problem. Could be clogged. If you have an 8” filter I would go up in filter size before fan size if you can’t get it hashed out. Also I would not use flex duct and make the duckt as short as possible.

The pre filter is a square cut out and taped over the exhaust port in the tent, should be pretty free air flow through there. The fan is in the 700s I believe, the filter I'm not sure about, the box said 550cfm but the company said it's a miss print and is meant to fit their 8" fan (vivosun). All 90 degree duct fittings attached(2 straightened out and one at 90 degrees, about 3 feet of travel).
On my last grow I can't remember if I used the dust filter on it or not, not sure I realized the importance of that on the last grow and think I kept it off for higher air flow so I'm thinking the c.f. might be getting plugged. After tear down in that specific room I realized it was extremely dusty in that room/my house because the insides of the fans and a simple register air intake between walls were completely caked with dust.
I'll go into my old journal and see if I can find any pics on if I used the dust filter.

 

[MichiganMedGrower]

You can put the prefilter meant to cover the can inside before hooking up the duct to it.

And without a prefilter they get clogged quickly. But you can extend filter life by knocking and shaking the can. Looking to hear loose carbon inside. This exposes more unused carbon.

 

[Rakin]

I would rinse the carbon filter out real good with high pressure water. Then let dry completely before use. You could also dry it in an oven if it fits. And if the prefilter doesn’t have much surface area it will restrict your flow also

 

[redi jedi]

You can put the prefilter meant to cover the can inside before hooking up the duct to it.

And without a prefilter they get clogged quickly. But you can extend filter life by knocking and shaking the can. Looking to hear loose carbon inside. This exposes more unused carbon.

Loose carbon is no good. If you can hear any shaking around the filter is junk. The carbon must be packed or else air will simply go around it.

 

[redi jedi]

I would rinse the carbon filter out real good with high pressure water. Then let dry completely before use. You could also dry it in an oven if it fits. And if the prefilter doesn’t have much surface area it will restrict your flow also

Pointless...you cant wash the contaminates out of the carbon. If the filter is small you could bake it in the oven.

If you did try to rinse out the filter with water you would have to dry it out somehow cause the water will plug the filter.

 

[Rakin]

Pointless...you cant wash the contaminates out of the carbon. If the filter is small you could bake it in the oven.

If you did try to rinse out the filter with water you would have to dry it out somehow cause the water will plug the filter.

Yeah ok. I’ve done it a shit load of times. Wash it from inside out flushing dust and whatnot. Then let it set out in the sun for a day or 2 then bag it for the next time I use it.