Houston we have a (whiffy) problem!

[Strangely]

So a little context first of all.

I have a small wooden cab running my first test grow. All is going pretty well, despite me displaying the sort of gardening dexterity usually reserved for those with large salamis for fingers.

Only thing is there's a definite smell after a couple of days on it's own (wick system). I have a layer of carbon air is pulled through and a roughly x2 passive intake.

I'm pretty sure I have no leaks for air to get past the carbon without being pulled through it.

So what do people reckon? The negative pressure at the intake has faded since the canopy has thickened up but the fan is still pulling plenty of air. Do I need to add the speed controller onto the fan that came with it to slow it down (temps are fine)? Maybe add a cover of carbon cooker hood sheet stuff over my passive intake?

Pray to the green gods? All guidance warmly received! Thanks in advance.

 

[Sgt.Stedenko]

Are you using the carbon on the intake or exhaust?
I'm confused.

 

[Strangely]

It's before the fan so on the exhaust (pulling).

My cab has a 251 cfm computer fan too!! Can you believe it!! You should have no problem at all.
How many cfm's is your fan? Sorry I forgot...
Did you mean you are getting 1 of the same scrubbers as I? Or the DIY one I had? The DIY let STANK through and I just could'nt be bothered anymore.My new one cost $100 bucks and its guaranteed for 3 years!! You don't do a thing except let it work.
The stink could also be pressure in your cab pushing the smell through whatever crack it could find..I had this problem too so I can help easier her than through posts..
let me know when you get this...
Thanks

Hi BC!

I wonder if it is a pressure issue? Maybe I should try turning the fan up what do you think? Plenty of air is pushed out at a good speed but negative pressure has dropped right down at the intake since the canopy has thickened up. I was thinking about turning the fan DOWN to allow more time being pulled through the carbon but my growers spidey sense was tingling telling me that was a daft idea!

 

[DiscoBiscuit]

So a little context first of all.

I have a small wooden cab running my first test grow. All is going pretty well, despite me displaying the sort of gardening dexterity usually reserved for those with large salamis for fingers.

Only thing is there's a definite smell after a couple of days on it's own (wick system). I have a layer of carbon air is pulled through and a roughly x2 passive intake.

I'm pretty sure I have no leaks for air to get past the carbon without being pulled through it.

A speed controller gives several benefits. Might knock the edge off enough to make smell limited.

Do you have a conventional scrubber or a sleeve or fabric? DIY? If so, is your carbon activated? Lab grade is best, pet shop/fish tank stuff is crap.

The negative pressure at the intake has faded since the canopy has thickened up but the fan is still pulling plenty of air. Do I need to add the speed controller onto the fan that came with it to slow it down (temps are fine)? Maybe add a cover of carbon cooker hood sheet stuff over my passive intake?

Could be unusually smelly. I've got a decent scrubber but it can't handle the occasional, momentary fart from the bad stinkers.

 

[Strangely]

Could be unusually smelly. I've got a decent scrubber but it can't handle the occasional, momentary fart from the bad stinkers.

It's Dutch Passions Blueberry so a bit of stinker. I thought it was a fairly aromatic smeling strain having smoked it. I must learn to assume nothing!

My layer of carbon is a home made drawer about 2 inches deep no leaks as I can see through the fan on top there's no light gettin out at lights on. Here's where I got my carbon any good?... http://www.activatedcarbontrading.co.uk/10.html

Thanks for the responses, sorry sgt s copy and paste fail from a PM!

 

[DiscoBiscuit]

Ooh, that looks like the good stuff. You've got the pellets (more surface area in the air stream.)

Two inches is pretty thick. If it's a consistent two inches, no problem. Otherwise, a thin spot could upset the mix.

You could possibly have stink if the fan isn't strong enough. Use a paper towel tube to isolate the smell if you can. If stink emanates from the exhaust hole, the carbon isn't doing it's job. You can tweak wall thickness and or fan speed to see what works best.

If smell is emanating from cracks in the cab, you might have positive pressure. Active intake? Another problem might be an internal circ fan that exceeds exhaust pressure. Never ran into this scenario but thought I'd mention it.

 

[Strangely]

Pretty sure no thin bits. Passive intake but this rang a bell...

Another problem might be an internal circ fan that exceeds exhaust pressure. Never ran into this scenario but thought I'd mention it.

I have the 80mm version of my 120mm exhaust fan acting as my circa fan, kicks off a nice gust, the stem is as thick as my thumb due to the movement it makes.

I think I'll try cranking the exhaust fan up and angling the circ fan up more.

My only worry is that I CAN smell weed a bit if I stick my nose up to the exhaust fan. Which kinda pisses on my cornflakes re some of these ideas as it points the finger at the carbon. Worst case scenario I'll add a bought can filter on top and grumpily chuck my makeshift carbon tray filter out the window. I could raise the lights a bit I guess. Easy enough to fit a 125mm can filter to a 120mm fan I wonder?!

 

[RJE231]

If it's an issue with smell coming from the exhaust I'd suggest getting carbon that's as fine as possible. The finer it is the more air will be scrubbed. The finer the carbon the more resistance that will add too, in these types of small grows it's pretty surprising how good of a fan/filter combo you'll have to invest in if you want to be completely smell free and not turn the box into an oven.

 

[DiscoBiscuit]

Try an inch or less of carbon. In the old days, I used a mesh pencil-can scrubber.

1 ea 4" mesh can

1 ea 3" mesh can

1 ea nylon hose

The wall was ~1/4" thick and I had the occasional burp of stink.

RJE is right, it takes a beefy fan/filter combo to be stink free.

But here's the deal. With no carbon, smell is consistent. With carbon, I can live with the stink that's gone as soon as it arises. It ain't perfect but it's close enough.

So if your stink isn't consistent, you won't get much difference tweaking a micro scrubber.

 

[Strangely]

Dear ladies and gentledudes, cheers for the advice. Interesting hearing the decent fan + scrubber to be totally stink free. My box is tiny (55cm tall) so I was hoping the Thermaltake fans I was using would do the trick, they're under powered to run quiet and still seem to be doing great.

Had a real good explore today with the little light cover hood off the top to have a real good look at the top of the carbon shelf with lights on. Turns out in the very corners on the back side where I couldn't see, there was a small gap! Worse was on one side where the drawer slides in where i didn't think I could fit a strip of door sealing foam, was a small gap too! No light was getting out but you could see from certain angles that the seal MIGHT not be 100%. So I pushed the carbon into all the corners properly, and added a strip of the door sealing foam to the one side I didn't think I could fit it and wedged that badboy in!!

I also turned my circ fan down and the exhaust fan up a tiny bit (need it to be quiet). So I'm hoping that will have done the trick! I'll post at least one more post in this thread after a few days to let you know if I'm 'stink free'!!

Thanks for the comments Disco Biscuit, RJE231 and Sgt.Stedenko. Really appreciate the sounding board IC gives me as the only mate who knows I'm growing doesn't himself (yet) so he's not much use in that respect. Thanks again!!

 

[Crake]

Ooh, that looks like the good stuff. You've got the pellets (more surface area in the air stream.)

DiscoBiscuit, just a tiny correction here. Pellets make for less surface area than the granulated stuff.

For example, if you took a one pound solid stone cube and one pound cube of sand, which would have more surface area? The sand of course. You can visualize this by imagining if you took the surface area of only the sand touching the outside of the cube--it should be roughly similar to the surface area of the solid stone, yet of course there's still the rest of the sand's inside surface area to count.

Or if you laid out all the sand in a flat sheet one granule thick and compared that to the surface area of the cube.

Strangely, it could be due to that same fact. You may want to instead try granulated activated carbon (the kind found in pet stores, for instance). You'll find this will greatly reduce the airflow so you may need more static pressure. An inch of carbon is enough, from what I've read.

Cheers. Best of luck.

 

[DiscoBiscuit]

DiscoBiscuit, just a tiny correction here. Pellets make for less surface area than the granulated stuff.

Check the mfg's link on that.


Strangely, here's another opinion. I've got the pet shop activated granular. It's crap. The stuff you've got looks like lab grade and your manufacturer re stuffs carbon scrubbers for a fee. If they use a vibration pedestal they'll do a better job than a typical diy.

The mfg's web sites advertises it for industrial (chemical) and air purification needs. IMO, you've got the right stuff. If it's made in pellets it for a reason.

 

[Crake]

Check the mfg's link on that.

I think you're referring to:

This size of pellet ensures a greater surface area between the air stream and the carbon bed to clean the air more effectively.

Greater than what?

 

[DiscoBiscuit]

You're correct and I see your point. IMO, greater than larger (granular or pellets.) I was unfair though, I called pet grade crap. I give it an 8 or 9 on average.

 

[Crake]

You're correct and I see your point. IMO, greater than larger (granular or pellets.) I was unfair though, I called pet grade crap. I give it an 8 or 9 on average.

I've been buying the pet grade stuff just because it's so accessible. Do you have any recommendations for some better stuff?

 

[DiscoBiscuit]

I plan to try what the op uses as soon as I'm out of granular. I've read several posts here suggesting pellets are better for stink. Buy yeah, the convenience of pet grade is a plus.

 

[de145]

Three things:

1) The pet grade is most certainly not crap. The aquarium type activated charcoal is cheap, easily available everywhere and definitely works as hundreds of people here will attest.

2) A trick to testing a carbon filter is to get some vanilla extract, put it in the grow area (don't pour it in, just open the bottle and set it inside) and smell for that through the system, it's very distinctive and a good test when your nose goes "skunk numb".

3) Another trick to sealing around edges really good for something that you need to remove like a tray or a door is to coat the moving side in grease or cooking spray, then pump a lot of your sealant (like silicone seal for example) onto the static non moving side, then slide in the tray or close the door and hold it in place until it cures. You can then slide out the tray or open the door and it won't have stuck to the silicone but it makes a perfect seal as it fits right into it.

 

[Strangely]

I've got the Hydro air purification size granule / pellets (3mm lengths of approx 1 mm across 'sticks'). I went to the effort of reordering when they added that option to their site, as I had the larger (4mm) general air purification stuff.

Bottom line - WE ARE STINK FREE!

I pestered the carbon supplier I linked to earlier in the thread to check delivery containers was unbranded etc so as not to shout 'Hey Neighbours, I'm Growing Weed!' if they took in the package. You pay by Paypal. Suits me.

I agree with the surface area comments but (as I think was mentioned earlier) that's a trade off between the force then needed (louder the fan) to pull the air through. I live in an old terraced house (neighbours either side, possibly not 100% air tight between houses) so need it to be very quiet and stink free (doesn't have to look stealth though). So now I've stopped being a massive tool and sorted the final gaps it seems a good balance with noise Vs smell, as I can live with the noise level and there's no smell.

I guess having it machine packed would increase resistance and fan noise etc etc again so I'll keep it in mind but think I just needed to totally fill it so the top screen helped push to the corners. All a learning curve though eh! Cheers for all the comments everyone!!

 

[DiscoBiscuit]

Glad you got it worked out.