Back to back scrubbers as part of ventilation

I'm going to set up a new room. Up to this point, my only grow space has been what is labeled as "Closet 1" in the diagram below. At 2'x5', a 600W hps coupled with a 265 cfm blower attached to a carbon scrubber has done a great job for me. I have had several successful crops over the past few years but I'm looking to upgrade.

I would like to keep "Closet 1" and make it the clone and veg room, make "Closet 2" a storage and reservoir room, and turn the main bedroom space of 9'x10' into the flower are. My plan is to use three 600W hps hung from the ceiling to do a vertical grow.

My questions and concerns here and now pertain to setting up the ventilation aspect of the room. This is what I'm thinking as of today:

1) Air intake from far side of the room would be an active intake, either the 265 cfm blower or a 465 cfm blower I also have already.

2) Exhaust #1 would be a large carbon filter (8" or 10") without a fan attached. Exhaust #2 would be a 6" inline fan (440 cfm) hooked up to a 6" carbon filter that exhausts into my attic. My thinking is that the only exhaust fan will pull air through both scrubbers as long as there is an airtight seal between scrubber #1 and closet #1.


Has anyone out there done anything like that, using a scrubber w/o a fan attached as a "pretreatment" for stinky air? What potential issues/concerns am I not thinking of?



Thanks all and take care,



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Just my but (and without calculating the size of fan you'll need), install the larger fan and filter for your exhaust port. Eliminate the 1st filter and install a light-proof vent in its place.

I would think that the biggest problem with a filter without a fan would be resistance (i.e one fan pulling through two filters).

Is using LED's/fluoro's for the veg/clone room to cut down on heat, an option?

messn'n'gommin' said:

Just my but (and without calculating the size of fan you'll need), install the larger fan and filter for your exhaust port. Eliminate the 1st filter and install a light-proof vent in its place.

I would think that the biggest problem with a filter without a fan would be resistance (i.e one fan pulling through two filters).

Is using LED's/fluoro's for the veg/clone room to cut down on heat, an option?

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I'm not too concerned about heat, the dual carbon filters are for extra peace of mind with the smell issue. Resistance is definately the main issue there but I figured with either a large enough fan or adding a fan to the first carbon filter as well I would get enough airflow to maintain negative pressure and ideal temps.

Thank you for your response,



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I suppose some would say it was a bit of overkill, but each of us has a different security comfort level and I have zero problem with your reasoning! I would be a bit wary of positive pressure, though. So, were it me, I would put the strongest fan at the end on the exhaust port.

3x600w flowering will need a 8in vortex fan/filter combo, hung nearly central and directly above bulbs. In vegg you could use one of your existing fans like that 465cfm also with matching filter. All of this for a well ventilated and "odor free" garden is quite impressive wen dialed ! Peace

messn'n'gommin' said:

I suppose some would say it was a bit of overkill, but each of us has a different security comfort level and I have zero problem with your reasoning! I would be a bit wary of positive pressure, though. So, were it me, I would put the strongest fan at the end on the exhaust port.

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Thank you for the input.

Fly by Night said:

3x600w flowering will need a 8in vortex fan/filter combo, hung nearly central and directly above bulbs. In vegg you could use one of your existing fans like that 465cfm also with matching filter. All of this for a well ventilated and "odor free" garden is quite impressive wen dialed ! Peace

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Thank you for taking the time to comment. My first thoughts were the same, that I would need an 8" fan and appropriately sized filter. After stewing on it a bit, I think that much air movement might be overkill. With ambient temps around 60f, I don't think I'll need that much exhaust to cool just 1800 watts in that size room. My main concerns are: 1) achieving negative pressure, and 2) using two carbon filters inline.

Any more input will be appreciated.



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I don't think the recommendation is overkill, however never had too much ventilation!! Use the insulated duct hose it'll be whisper quiet too

At certain times many of us have considered filtering two rooms thru one scrubber, but come to realize there's a benefit to a proper set up

Peace bruvvie

Fly by Night said:

I don't think the recommendation is overkill, however never had too much ventilation!! Use the insulated duct hose it'll be whisper quiet too

At certain times many of us have considered filtering two rooms thru one scrubber, but come to realize there's a benefit to a proper set up

Peace bruvvie

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I also don't think an 8" fan would be overkill to the point of being detrimental in this size setup but there is definitely the possibility of having too much ventilation. I've actually had to deal with the effects caused by too much airflow, this is one of the better explanations I could find on this site:

Retardo Motabon said:

Yes, of course. Anything can be overdone. One factor is that transpiration increases in the plant causing a reduction in growth efficiency due to increased demand on roots to maintain water balance in the plant. Stoma close when wind is too strong to conserve moisture. therefore Co2 intake is reduced in the plant. Agitation from strong wind also causes inefficiency in the translocation of nutrients within the plant. energy is wasted repairing wind damaged leaf tissue. many studies have been done on this. Yields suffer from too much wind. Dry weight of roots and shoots is increased from high wind causing a decrease in crop weight or high winds lower yield. Picture yourself outside in an open field. A nice breeze is pleasant, but when it gets really windy its not pleasant anymore. You will also dehydrate faster. hope this helps.
RM

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I don't want to go too much bigger than I have to with the fan (and corresponding filter) for a few reasons: noise, venting more air than is necessary into my attic, cost, and size (particularly the filter). That being said, 8" is probably the better choice. Maybe I already know the answers, maybe I'm just in denial, maybe I just need someone to help me talk it out. Regardless, thanks again for your thoughts!



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