Help with ventillation setup for cooling lights

[simonH]

Hey guys

 

I've finally started my first grow - I got some afghan seeds from MJ seeds, germinated in kitchen towel, then planted in a jiffy pellet, then once the roots began showing, removed the netting and placed into a soil mix of worm castings, compost, perlite, peat and potting soil. They are growing awfully slowly though, its been two weeks and theres only 3 sets of leaves, and they aren't tall not sure why - just germinated two more seeds, and trying those two in Coco - the seedling has popped through after two days of the seed with taproot being in the coco, and the the seed should be shed soon.

 

I'm using a 400W HPS light for now, and using a toilet room for the grow. The ceiling has a vent on the top, and this leads to the outside, there is no fan or anything apparently (according to building management), its basically ducting that leads outside.

 

Its getting a bit hot in there - with a oscillating fan running, the temp is around 29.5 C, and 45-50% humidity.

 

The light is an air cooled hood.

 

I just purchased a centrifugal fan, ducting, and a carbon filter.

 

I'm hoping to achieve both cooling and getting more air into the room with this.

 

The duct is connected to the outside world, so Could I vent there and draw there too?

 

I also had the wacky idea of venting/drawing air from the sink. I figured if you connect to the drain hole, its all pipes that lead to sewerage, so should be perfect for venting? Even connect to the toilet?

 

I drew 2 diagrams, what do you think? Neither? (please excuse the kindergarten level drawings and writing!)

 

Ive also read its best to push air rather than pull. Thoughts?

 

Thanks for any help guys.

 

 

 

 

 

 

 

 

[kelossus]

Ducting is fine if you just want to exchange stagnant air. You need some form of fresh air being pumped into the room also.

 

Exhausting stagnant air is one part you also need a fan pumping fresh into a grow space, especially if that space is small and concealed.

[Ferrethead]

Definitely have your carbon filter sucking air from as high as possible in the room........heat rises remember. So you want to remove the hottest air.

 

You don't need an active intake for a grow that small. The cracks under the door will draw in enough fresh air if your actively pushing out enough. I'd be more interested bringing in air from underground than exhausting there. Simply because the air from down there, although might smell like arse, is cooler.

 

With a properly setup and sized carbon filter, you won't smell anything outside, especially venting through the ceiling.

[simonH]

Thanks guys.

 

 

Definitely have your carbon filter sucking air from as high as possible in the room........heat rises remember. So you want to remove the hottest air.

You don't need an active intake for a grow that small. The cracks under the door will draw in enough fresh air if your actively pushing out enough. I'd be more interested bringing in air from underground than exhausting there. Simply because the air from down there, although might smell like arse, is cooler.

With a properly setup and sized carbon filter, you won't smell anything outside, especially venting through the ceiling.

 

Thanks for that. When you say bringing air in for underground, you talking about the sewerage? How do you think I should set it up.

 

Also with a carbon filter, is it best to suck air through it then expel the filtered air using ducting (like in my pic), or I was thinking to have the carbon filter as the last link in the chain, and blow air through it? So

 

Fan -> Light -> ducting -> cabon filter.

 

It would be good if you get filter that had an input and an output, so the air goes through the filter,  then you have a duct that you can direct to wherever.

[louise]

If you want to be able to grow through summer you will be much better off setting up the light cooling separately from the room extraction.

 

Cooling the light

 

inline fan  > cooltube or aircooled hood > exhaust

 

Extracting the room/tent

 

carbon filter > centrifugal fan > exhaust

 

 

For the relatively small cost of buying and running an inline fan you can have a much cooler environment.

[DoctorWho]

Run the shade and exhaust separately.  You can keep the air used to cool the light out of the grow area so it doesn't require a carbon filter and as that would remove most of the heat before it can enter the grow area your extraction fan won't need to work nearly as hard to keep the place cool.  That would make growing over summer much easier for you as well which can make the world of difference.

 

If you can't buy any more gear though go with your first drawing but with the carbon filter up as high as you can get it.  Its far from ideal and will likely need upgrading in the future but if you have to make do with what you have it would be your best option.

[simonH]

My room doesnt get hot, it basically underground, and is usually quite cool, even in summer,  jut the heat from the light warms it up to around 29-30 C.

 

Whats the difference between an inline and centrifugal fan? The one I have now is centrifugal, and apparently they are better than in line?

 

The inline ones Ive seen are cheaper than centrifugal, so for that, say if i got one, I could connect ducting to the duct in the ceiling, have a fan blowing air through the cool tube, and have it venting in the ceiling too, which leads to the outside? This way I wouldnt need a carbon filter on that as its taking air from the ceiling and exhausting it there too? 

 

And then have the carbon filter venting to the outside too via the ceiling, and rely on crack under the door, leaving the door open etc for fresh air?

 

So the ideal would the the second drawing, and a separate system with the carbon filter, venting to the ceiling too? I figure the celiling duct is connected to the outside world, so there should be plenty of air, espeically when its windy outside.

[louise]

The power is the difference. To run a cool tube or air cooled hood you don't need much power to blow or suck the air through, but with a carbon filter you need the gutsier fan to pull or push air through the filter.

[simonH]

I see. So use my centrifugal fan for the filter, then get a cheap inline fan for the cooltube. Do you think I could draw cool air from the ceiling and vent there too, as well as vent air from the carbon filter there too?

[DoctorWho]

I see. So use my centrifugal fan for the filter, then get a cheap inline fan for the cooltube. Do you think I could draw cool air from the ceiling and vent there too, as well as vent air from the carbon filter there too?

Investing in quality gear the first time round is the second best thing you can do when beginning to grow.  The first is planning it out perfectly so you only need to buy equipment once.  You're planning now which is great but if you stinge out on equipment you're gonna have a bad time no matter how good your plans are.

 

I also wouldn't worry about temperature at all if you get a max of 29-30c in the grow area as its pretty much perfect for growing cannabis.