4kw Sealed Stealth Attic Grow Running Hot Cooltubes?

I've been working on this room for quite a while now and researched til I was blue in the face. I just have a couple questions for you guys that I can't seem to come to a conclusion on.

Heres what I have:

Michigan Climate

Grow room dimensions:
Pentagon shaped and straight 7'w x 20'L x 6'T at peak

Attic dimension:
Triangle shaped and straight 20'w x 30'L x 6'T at peak

Equipment:
4 - 1000 watt digital ballast
4 - Hydrofarm Radiant 6" air cooled hood
4 - 6" 400cfm Inline fan
1 - 24000 btu dual zone mini split a/c (not yet purchased)
1 - dehumidifier
1 - humidifier
4 - 6" duct muffler
1 - water cooled co2 generator (hydrogen knockoff)
1 - digital co2 controller
6 - 12" oscillating fans

Grow room insulation:
3.5" of pink fiberglass insulation(r rating=r13) with 2" foam board (r ratings=13). Total r rating of 26


Attic & roof ventilation & insulation:
Besides the grow room, the attic and roof is not insulated. I plan to use spray foam and spray the underside of the metal roof at some point(when i can afford it) to help with cooling efficiency due to my fans for my lights pulling air from the attic space and no way to change that. However it will cost about two grand so hopefully i can hold off on that. The roof has no ridge vent or access to soffits. It does have a gable fan, 4 - 6" open vents, and one larger open gable vent. Gable fan shuts off during light on to allow air flow for cooling the lights.

Grow room ventilation:
No in. No out. completely sealed with panda film.

light ventilation:
Each light has its own 6" x 20' aluminum rigid duct run with two 90degree bends. Each light also has its own 6" 400cfm inline fan mounted at the end of its duct run.


My issues:

My fans are too loud and my hoods are too big and hot.

I'm considering switching to cool tubes to increase cooling efficieny and space within the grow room. I'm also considering switching the fans from pulling at the end of each duct run to pushing at the beginning of each duct run to cut down on noise. I know inline fans are more effective pulling but hopefully switching to cool tubes will soften the blow due to the lack of turbulence created by pushing air in hoods versus a duct shape cooltube. I have never pushed air with inline fans so I have no perspective so i would like to hear some other opinions on that subject as well.

So I've come up with some cooltube options.. Let me know what you think.

A. Replace 6" hoods with 6" cooltubes. Ducting size the same. Each light has its own duct run. 6" 400cfm inline fan per light. (piece of cake)

B. Replace 6" hoods with 8" cooltubes. Increase ducting size to 8". each light has its own duct run. 8" 720cfm inline fan per light

C. Replace 6" hoods with 8" cooltubes. Increase ducting size to 8". Daisy chain two cooltubes together so each pair of lights have their own duct run. 8" 720cfm inline fan per pair of lights.


I'd love for option C. to work out since it would be relatively cost effective and open up alot of room in the grow room since it would have half the ducting the other two would have. My concern is daisy chaining. I have no experience with daisy chaining and not sure how big of a difference it would make if any.

Option B. seems like it would be the most effective but also the most expensive and would also take up the most space in the grow room.

Option A. would be an easy transition and the most cost effective. However I'm concerned using 6" cooltubes would not be adequate since I'm having issues with my 6" hoods that i have. unless the cooltubes are that much better at removing heat than hoods. I've never used cooltubes so I wouldn't know.


Thanks yall
TIME TO BURN!

Very we'll laid out question go with option c the 8inch cool tubes will be considerably cooler than The 6 more air will flow through and more freely also the pull the air with the fan and if noise is an issue put the fan in a Rubbermaid container run the ducting thru and cut holes for the ducting then put the lid on the Rubbermaid and fill it with the insulation foam your talking about

I'll subscribe if you have some pics up soon let's see it man..... Lol stop by my thread anytime and check it out I'm shut down at the moment had a 2 yr run at my old house.... The 2200 watt good neighbor grow it's in my sig

Got some pics? Lets see your setup. Also, what is the constant temp and RH currently in your sealed setup? Also, if trading out for cooltubes, I'll take a couple of those hydrofarm hoods off your hands...

Right on. Nice I'll check it out. I like hearing option c. Thats the one I favor. That rubbermaid container is one hell of an idea. I use mufflers but that should help much more. Thanks man!

I'll get some pics up soon. Right now I'm just test driving. I'm not running yet b/c i need my last piece of the puzzle. Which is unfortunately a 2000$ mini split lol. Besides that everything is in its place ready to go. I'll prob sell my hoods so I'll take em down and get some good pics for you. They are like new.

With only 6 feet of height I think you would find things much easier to manage with lower wattage bulbs. 400 or 600 watt would be better suited. Also when running a sealed, your plants will produce a ton of humidity, running air cooled lights and using a dehumidifier is often less efficient than using open hood fixtures and a properly sized air conditioner. You will still require a dehumidifier at night.

A 1k really should be 30-36" above the tops, even when cooled.

That's really interesting. So the air cooled lights won't keep the humidity down on its own when lights are on but a open hood fixture would? I did not know that...Never ran a cycle with open hood fixtures before. Thanks man good info. I'd consider biting the bullet and losing some efficiency by letting the dehumidifiers run and cranking that a/c b/c this is a medical grow thats limited to 12 plants and 20' x 7' of floor space. I'm trying to do a 16' x 4' scrog and I really want to try to get the most out of the space and each light (grams per sq ft of canopy & grams per watt) but also not trying to beat a dead horse if it won't work well. The 30-36" away from a properly cool 1000 watt light would be a deal breaker...I thought 18" would be sufficient.

I'm scared to run open hoods (even 400s or 600s) in such as small space only because I have no successful experience with open hoods and i know how much heat these things put off. However if the properly sized a/c gets it done...then this setup would have many added benefits for me and this is something I need to consider. The only negative would be a large drop in yield.

Good advice. Thanks man

crosby87 said:

That's really interesting. So the air cooled lights won't keep the humidity down on its own when lights are on but a open hood fixture would? I did not know that...Never ran a cycle with open hood fixtures before. Thanks man good info. I'd consider biting the bullet and losing some efficiency by letting the dehumidifiers run and cranking that a/c b/c this is a medical grow thats limited to 12 plants and 20' x 7' of floor space. I'm trying to do a 16' x 4' scrog and I really want to try to get the most out of the space and each light (grams per sq ft of canopy & grams per watt) but also not trying to beat a dead horse if it won't work well. The 30-36" away from a properly cool 1000 watt light would be a deal breaker...I thought 18" would be sufficient.

I'm scared to run open hoods (even 400s or 600s) in such as small space only because I have no successful experience with open hoods and i know how much heat these things put off. However if the properly sized a/c gets it done...then this setup would have many added benefits for me and this is something I need to consider. The only negative would be a large drop in yield.

Good advice. Thanks man

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I know that there's much debate on this but 18" away from a 1k in my experience isn't really that good. It does depend a great deal on your hoods etc. but I have run water cooled systems that produced no heat at all but still cooked the plants if too close. My best results were still at 30-36" away from the tops. You need to provide the right amount of light, not too much and definitely not too little. Take a look at all of the large scale grows, they have their hoods up at 3 ft. and no they're not raising them for the photo.

A sealed room is a balancing act, every setup has it's own balancing point. What works for me may not work at all for you. I'll only convey my experiences to you growing sealed.

An open bulb 1k requires 4000btu of ac, While that AC is running it is dehumidifying the air. So we can reduced our running equipment by 50% by opening our hoods and running an AC by day and a dehuey at night. Keep in mind, a dehumidifier is just another refrigeration unit, just like your AC, it just exhausts it's heat back into the room.

Having a high output fan sucking air through your hoods often leads to increased Co2 usage. Sealing everything up so there are 0 air leaks can be quite difficult. Even a small leak can drain a 50lb bottle in days instead of weeks.

Like I said it's a balancing act. You find that you are removing heat with your fans only to be adding it back with a dehuey and then running AC too. Why not let the heat enter the room and keep your AC running to accomplish the dehumidification. Much simpler IMHO.

Yes 18-24 is good on a 600. a 1k is a different animal. Spend a few bucks on a light meter and find the sweet spot that your hood works at. There will be a point that is has the best coverage.