Help with fans pls

Want to be a good farmer!

Want to be a good farmer!

Member
Hi there everyone ! Total newbie here.
My problem is that this is my first ever grow and I have had nothing but problems with condensation in my tent..
I have a 4" inline fan on my carbon filter that just is not capable of much I am thinking of buying a 5 " inline fan and a 5-4" reducer fitting so it will connect to my 4" filter..
Will this be ok ? Also can I use the old 4 " fan as a intake fan through the bottom sock on my tent? I also have a 6" clip on fan blowing all the time just to stop the tent getting so wet inside ... Will my swap around of fans work? And help this problem as I'm still in veg and don't want the desk fan on through the whole 18hrs I have the light on .... Sorry if this is a repeat question just need some help... My tent is 0.8x0.8x1.6
 
dirtyrigger

dirtyrigger

Member
Carbon filters have max cfm ratings just like fans, I think you'll have better results stepping up to a 6" fan and a 6" filter to match. Your old fan will work for intake but I have to ask what are you using for intake right now?

Before you run out and buy anything though, what is your relative humidity and temperature inside your grow? And what is the rh and temp of the ambient air you're pulling into your grow? If you're getting condensation inside your tent I'm thinking your humidity is probably high enough that you might get better results keeping your current exhaust setup and adding in either a dehumidifier or a small a/c.
 
ChingOwn

ChingOwn

Well-Known Member
Want to be a good farmer! said:
Hi there everyone ! Total newbie here.
My problem is that this is my first ever grow and I have had nothing but problems with condensation in my tent..
I have a 4" inline fan on my carbon filter that just is not capable of much I am thinking of buying a 5 " inline fan and a 5-4" reducer fitting so it will connect to my 4" filter..
Will this be ok ? Also can I use the old 4 " fan as a intake fan through the bottom sock on my tent? I also have a 6" clip on fan blowing all the time just to stop the tent getting so wet inside ... Will my swap around of fans work? And help this problem as I'm still in veg and don't want the desk fan on through the whole 18hrs I have the light on .... Sorry if this is a repeat question just need some help... My tent is 0.8x0.8x1.6
Click to expand...

I forgot to mention always put intake at the bottom and exhaust at the top cause hot air rises
 
Want to be a good farmer!

Want to be a good farmer!

Member
dirtyrigger said:
Carbon filters have max cfm ratings just like fans, I think you'll have better results stepping up to a 6" fan and a 6" filter to match. Your old fan will work for intake but I have to ask what are you using for intake right now?

Before you run out and buy anything though, what is your relative humidity and temperature inside your grow? And what is the rh and temp of the ambient air you're pulling into your grow? If you're getting condensation inside your tent I'm thinking your humidity is probably high enough that you might get better results keeping your current exhaust setup and adding in either a dehumidifier or a small a/c.
Click to expand...

The temp inside the tent is a steady 84-86 down by the plant up top it's was around 90! Since I have had the clip on fan running condensation is nearly 0% not sure what the humidity is a waiting for the ph tester and humidity thing to come in the post ! I'm not using a intake fan just the inline with filter and desk fan both on trough out light and run for 15min extra after light goes out the plants are 23 days old ! image.jpgimage.jpg
 
ChingOwn

ChingOwn

Well-Known Member
Keep the fans on all the time if you can... temps need to be in the low to mid 70's or you might get foxtails or other heatstress badness
 
dirtyrigger

dirtyrigger

Member
You're temps aren't too bad, but what I mean by that is they are what I consider the upper limit of allowable.
Leave your fans on 24/7. It takes longer than 15 min usually to remove all the heat from your lights after they go out. It's also good because your plants still transpire when the lights are out so they still are putting moisture into the air and needing fresh co2.

As for intake it's ok not to have a fan, but you should have a passive intake opening at least 2x the size of your exhaust fan. In your case 6" round or a 5"x5". Make sure it's light proof, insulated flex duct in a gentle S shape works or look at the diy forum for a couple different light trap designs. You really need to have some form of air intake to make your system work it doesn't really matter whether it's active or passive.
 
Want to be a good farmer!

Want to be a good farmer!

Member
dirtyrigger said:
You're temps aren't too bad, but what I mean by that is they are what I consider the upper limit of allowable.
Leave your fans on 24/7. It takes longer than 15 min usually to remove all the heat from your lights after they go out. It's also good because your plants still transpire when the lights are out so they still are putting sure it's light proof, insulated passive.
Click to expand...
Thank you so much laymen's terms I work well with. I have fans on all 18hrs that the lights are on then I keep the fans going on a extra 1/2 hour after lights off then they are back on same time lights go back on ! Going to buy a bigger fan for the filter my 1 at the moment is only 105m3/h going to up grade to 1 that at max is about 260 odd m3/h ! Hope that sorts the heat better so I can get the temps I want dialled in !
 
Greenhouse;save

Greenhouse;save

Well-Known Member
Yea for the size of tent u r working with its easy to get a buildup if I were u I would defo install an intake fan preferably variable speed u could get a 4inch pc fan and connect it to one of those 12v speed adjustable adapters allows u to control the speed and my 4 inch 12v pc fan does a better job than my 4inch expelair and as I say I can control the speed and very little lecky being used aswell.....
 
Greenhouse;save

Greenhouse;save

Well-Known Member
And beef up u ur fan on ur filter that's far to small imo to b running a filter up it to at least mid 200cfm3 to solve ur probs...
 
dirtyrigger

dirtyrigger

Member
Yes I just did the math and realized how weak your fan is. I don't think in metric well at all, lol, but you should be looking for something at or above 320cm/h.
 
BluJayz

BluJayz

Well-Known Member
Its always good to have your exhaust and inside fans turn on every hour or two while the lights are off to evacuate moisture and keep the leaves dry. Get a 15 min timer for them.

Also Ideal growing temps is 68-79F. You can go as high as 85F but most plants will glow growth and stop near 85F.

Here in AZ I see outdoor plants flourish in 110F but they are already 7 feet tall by that time and have roots deep in the earth assisting in fighting the heat.

As for your fan I can attest to a max fan pro 6'.
Medium Speed – 291 CFM – 52 Watts
Medium High Speed – 379 CFM – 60 Watts
High Speed – 420 CFM – 69 Watts

It will keep it ice cold in there. I've used 6' 8' and 10'. Best/quietest fans. Built for your job.
 
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Greenhouse;save

Greenhouse;save

Well-Known Member
Bottom line is get yourself an intake to keep the air flow clean and a bigger fan for ur filter because at the end of the day......
 
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