Fans

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

Match the cubic feet per minute (CFM) rating of the inline fan to the cubic feet of your garden area using the formula Lx W x H. Keep the fan on 24 hrs is best. INtake and exhaust are mandatory, so yes its a good idea PLants look happy , keep on rockin it

Cheers for that my mind can rest !! The fan I have is 105m3/h ... Just is not shifting heat well not sure what that converts to in cfm?? Sorry totally new at this

Dude if there is condensation on the walls of your tent you need to lower the humidity in the room. Is a dehumidifier an option? Ventillation is vital to happy plants and you may need a bigger fan..always go bigger on the fan if you can. A better quality 4inch fan like a vortex will do a better job for you. IME an intake fan does little..a passive intake works fine. Passive just means an opening for an intake..no fan..just be sure the passive intake is at least twice as big as your exhaust. So for a 4inch exhaust you'd need an 8 inch hole.

yes i as well am not a fan (hat har pun intended) of using a intake fan. you just need a bigger fan for your light and filter. by getting a 5' and reducing it to 4' your lowering your CFM. to get CFM just convert your meters to feet.

also a good oscilating fan inside will help with condensation. it will help evap it and then your bigger fan will remove it.

Was looking at a dehumidifier !! I understand about the passive in take and you say make a hole ? Were do I make a hole surely I don't want any smell able to escape! What's wrong with using the old 4" fan as my new intake ? Rather than leaving a hole open if that makes sense ....?

@ retired I mean reducing the 5" down to 4" to fit my filter as I don't really want to fork out on a new filter as this 1 not even a week old ! Surely the 5 will still have more grunt even with a 4" filter on it than the fan I have now is ?

Want to be a good farmer! said:

Was looking at a dehumidifier !! I understand about the passive in take and you say make a hole ? Were do I make a hole surely I don't want any smell able to escape! What's wrong with using the old 4" fan as my new intake ? Rather than leaving a hole open if that makes sense ....?

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To be passive you'd leave the fan out and suction from your exhaust fan will keep the smell in. Your tent should have another vent you can open?

RetiredMatthebrute said:

yes i as well am not a fan (hat har pun intended) of using a intake fan. you just need a bigger fan for your light and filter. by getting a 5' and reducing it to 4' your lowering your CFM. to get CFM just convert your meters to feet.

also a good oscilating fan inside will help with condensation. it will help evap it and then your bigger fan will remove it.

Click to expand...

no clue said:

To be passive you'd leave the fan out and suction from your exhaust fan will keep the smell in. Your tent should have another vent you can open?

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Now I understand sorry for being dump I have a sock right at the bottom of the tent I can use ! Just need a bigger fan and filter

Are you using a centrifugal blower or a whimpy axial "booster"?

SnapsProvolone said:

Are you using a centrifugal blower or a whimpy axial "booster"?

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It's like a bathroom / kitchen extractor fan that came with the kit

http://hydrofarm.com/product.php?itemid=8095

That'll move the air, will make more noise.

Blow hot air out the top, passive vents in bottom allow cool air to replace exhausted air.

The centrifugal type copes better with static pressure losses such as those commonly associated with filters and duct work.

Basically, it will better pull air thru a filter and push it out the duct.

SnapsProvolone said:

The centrifugal type copes better with static pressure losses such as those commonly associated with filters and duct work.

Basically, it will better pull air thru a filter and push it out the duct.

Click to expand...

Thank you for you input on this .

Need to figure the cfm's (formula) needed for your grow space. Also air exchange should be no longer than 10-15 seconds (old air out new air in) in grow space

looks like your sorted here, hope all works out

I don't recall seeing what light you are using?

Here's my take on fans. (By using m3/h I'm assuming you are in the UK)

250w hps - 4" fan - 180m3/h

400w hps - 5" fan - 280m3/h

600w hps - 6" fan - 480m3/h

1000w hps - 6" fan - 700m3/h

Now the above is very crude way of working out fan power required but it works.

SYSTEMAIR RVK FANS are some of the best to use for exhausting.

Filters are usually m3/h rated too.

If your fan is of a higher m3/h rating than the filter then you will get smell issues.

You should aim to extract your grow area between 1x-3x per minute. If you need to exceed 3x per minute to deal with heat then AC should be considered.

When calculating fan power its not just a (WxLxH)x60 = m3/h needed.

Intake temps play a role, as to do carbon filters, duct run lengths, ducting bends, light wattage, air cooled or open reflectors used.

Each of these things require additional %'s of m3/h to calculate fan powers.



J