Medium Sized NGB Cab - Ebb+Flow, 600w HPS, need constructive criticism

[nickelrw87]

Aloha All! This may be my first time posting - but have been (like many) a lurker for years and years. So Hello - this is me~!

General information at a glance.
1 month perpetual grow, 1 plant per month.
Grow cab will be located inside my bedroom, I am a legal medicinal patient in Hawaii so ambient temps are sometimes wacky. Night is sometimes cool - so my run schedule would be to have the flower light on during night. I do have window A/C rated for 5000 BTU, cooling the cab room - which is 12'x11' - i plan on testing without A/C because that will bring my electric down immensely!
Lighting exhaust will exhaust into the upper chamber, where the flower and veg chamber exhausts to. Passive intakes will be on the outside wall of each grow chamber, with both the room "exhaust" will be on the top of chamber, above the lights.

From what i understand, 1 grow per month, for a 8 week flower cycle. Start 1st plant - veg for 3-4 weeks, place into flower. Start 2nd plant when 1st goes into flower. Place 2nd plant into the flower chamber in 3-4 weeks, start another plant. At this time 1 plant will be 4 weeks into flower when the 2nd vegging one goes into flower, with 1 just starting veg - rinse and repeat. I am not stuck on this perpetual grow, so i left some room in the chambers to try other styles.

Im putting this here for feedback - but make it worthwhile and constructive please

The cab will be 6'x3'x6' (72"x36"x72")
- 72 inch - 6 feet long
- 36 inch - 3 feet wide
- 72 inches - 6 feet tall

It will have two grow sections. One for flower and one for veg/mother (if i decide to have a mother). i assume i can put both the mother and clones in the same compartment as they both require 18/24 hours of light. It will be a large NGB style cab, with 3 compartments overall, 1 for flower, 1 for veg/mother and 1 for electrical stuff. The section sizes are as follows (all without growing equipment):
- Flower Section - 48"x36"x59" (4'x3'x4'11")
- Veg/Mother section - 24"x36"x48" (2'x3'x4')
- Electrical Section(above veg)- 24"x36"x72" (2'x'3'x6')

The ventilation:
- Lights and A/V Hood ventilation
- Two semi-separate cooling systems - both end up in a single chamber
- Both ventilation systems will be directed into the top 3rd chamber with the electrical
- Carbon scrubber rated for 440CFM will be used by a 400CFM inline fan - sucking -. Filter will be located in the 3rd upper chamber where both veg and flower will be vented into
- all the intakes will have the PVC pipe bends on the inside only. It doesn't need to be stealth but it's just looks ugly to me.


From what i read about HVAC ventilation, it takes 1sq ft of open inlet per 300 CFM. So in my case, 400 CFM would be a little over 1sqft - 1sqft is 144sq inches. I will have 7 holes for intake overall - 6 total for both chambers (3 apiece) and 1 for the A/C hood. I imagine that to keep negative pressure you should be at that level or a tiny bit below? Please correct me if I'm wrong. Anyways, from the above website my calculations came to 6 holes, each at 5.5inches in diameter. There are a few holes internally, which I'm not really sure how to calculate that into the equation, any help with that would be kickass.

The lighting will be:
- Flower - 600w HPS Air Cooled sealed hood
- Veg/Mother - 125w fluorescent - 4x28w

More Shit:
- Flower will be a Ebb+flow system with rockwool - homemade system BTW
- Fert will be whatever i get at the hydro shop - any suggestions? I read Fox Farm is supposed to be super good. Id love to go 'organic' but im not sure if they have true organic hydro nutes.
- I want to use the veg for clones - but since im going to be doing so little cloning, i doubt the plants will get that tall, especially since im vegging for 4 weeks only - so there may be a better way to utilize the above space...
- much smaller Ebb+flow with Rockwool for the clones as well.
- Below is a crude diagram of the system setup. Both Fans are 400 CFM inline.

Questions:
1. Air takes the path of least resistance - so by having the HPS light vent into the top chamber, will that lower the air flow thru the actual flower chamber thru the passive ducts? Any Suggestions?
2. Will the 400CFM for the filter be enough power to create the negative pressure for the passive intakes?

 

[nickelrw87]

if anyone needs metric ill be happy to convert for you stoners

 

[nickelrw87]

damn not a single post - :/ i specifically choose 420mag because the people are much more helpful (and "professsional"). Ill post it on a few other forums too - so feel free to find me and comment on that thread if your more active on those forums.

 

[nickelrw87]

same results with the other posts on other sites...maybe its just to advanced or something. No damn replies, no nothing. I see posts with dumber shit with more replies.... I dunno im outta here i guess

 

[Growingnow]

I would move the fan on your lamp to have it blow the air through the bulb not drawing the air seems like you are going to cut down on your air flow.

 

[Growingnow]

 

[nickelrw87]

So you have your fan sucking in air from within the grow box across the bulb? Hmmm i think that may be a much better choice for me. Im starting the actual construction today - but it has to be a step by step cuz im broke lol

 

[J189RFC]

I don't think you need the extra fan. I'm only running 400 but it never gets overly hot. I keep my girls between 6-12 inches away and if you have a cool tube you should be fine. To feel safe though, put the money from the fan leading out of the cool tube and put it into a slightly bigger exhaust for the Carbon scruber. My 2 cents.

Also I'm assuming you'll have a fan inside both cabinets blowing on the girls to make them strong and keep them slightly cooler?

 

[nickelrw87]

Correct about the fans inside the rooms themselves. I live in Hawaii so it gets pretty hot during the summer, so im trying to compensate for the extra heat, which is why i have the two fans.

Now im wondering if ii should draw the air to cool the light from inside the box instead of having a dedicated intake for it. Thanks for everyone's input - i was feeling a bit left out!! lmfao

 

[J189RFC]

I was thinking about that. You might just want to draw the lights air from the cab itself. Then you don't even need the extra passive cut out. 1:1 air intakes. Maybe position your passive intake on the "opposite" side of where the tube is drawing? Sorry, been soooo This might not all make sense!

 

[nickelrw87]

haha - yea i think i may just draw the air from inside the cab. I just framed the footprint/floor. Was there a photo attached to your last post i dont think it went thru if you did...

I think we all been a bit haha I make sense in my head, but never comes out right when i express it

 

[nickelrw87]

new updated design. Can be changed still - i was thinking since the intake in the flower is on the outside wall - the exhaust for the light can switch sides so it sucks in from the opposite side of the flower space intakes.

 

[nickelrw87]

So a year later... DUN DUN DUN im back with a working plan...

400 CFM rated scrubber. 400 CFM inline Hydrofarm fan. 600W HPS air cooled hood (sealed), 110w Veg chamber fluorescent T5's.

Not bad so far - the intake has to be huge to accomodate the small box - its like 180 sq ft all together.

 

[nickelrw87]

So far its been working great. BIG BIG tip - you MUST calculate the correct intakes. Im still working this kink out, but other than that its pretty slick

 

[Ancho]

I've become a believer in the past month for the need of two fans, one dedicated to the carbon filter the other fan on the light. The way you have it set up right now at the start of the light period all air temps inside the tent and out will be close. But as the day progresses the air in the tent is going to be heating up. So now you will be cooling the light with air hotter than it was a the light cycle start, as the day goes on a cycle of slightly warmer air is being used to cool the light continues and now even warmer air is being used to cool the light, temps in the tent go up. Consider the second fan so you can aways draw cool air from outside the grow area to keep the light cool. Just made that change in my tent and saw temps drop by a minimum of 5 degrees, huge deal the way the plant responded.

 

[nickelrw87]

aloha Ancho! Thanks for joining me in my thread.

The fan is blowing all the hot are out the window, and the window has a A/C going 24/7. I do understand the concern of the Flowering room getting warm, then transferring into the veg room thus making that room a tad bit hotter in itself. My solution to that, is to keep the abient room temperatures as low as they can be.

I have thought about it, but as of right now - my amps are riiiiight about hitting the max. My room mate and I now need to plan to vacuum during the dark period of the tent or the fuse blows.

I was thinking a shitload of these little things... Midget Louvers.

And a shitload - i mean like maybe 12 of these things.

 

[Dantes Monkey]

So a year later... DUN DUN DUN im back with a working plan...

400 CFM rated scrubber. 400 CFM inline Hydrofarm fan. 600W HPS air cooled hood (sealed), 110w Veg chamber fluorescent T5's.

Not bad so far - the intake has to be huge to accomodate the small box - its like 180 sq ft all together.

I would increase the capacity of your scrubber, or run your fan at slower speed. I've heard people say that the CFM capacity of your carbon scrubber should be double the CFM of your fan.

Also, your flowering plants will be much stinkier than your vegging plants. With your hood, fan, and ducting downstream from your carbon scrubber, you have more potential for air leaks. I would put the fan directly on the scrubber and let it push air over your light.

Better yet, run two fans. One pulling from outside, pushing fresh air over your bulb creating positive pressure in your hood and venting back outside the grow room. And another on your scrubber pulling through the filter and pushing directly out of the room, creating overall negative pressure in your grow room.

 

[nickelrw87]

Hey Dante! thanks for checkin this out.

At the time - space is a bit small for more than one fan, and i dont have enough amps in my fuse box. What i did to combat the semi-high temps, was to run a 4 inch dryer vent from the A/C vent to the box. So now its pulling in cool air from the room, and a bit of direct cool air from the A/C. Been around 82-ish now, which i can dig, because even if i grew these little fuckers outdoors, it would be about 87 degree's all day on it.

 

[Dantes Monkey]

no worries, i would still put that fan directly on your scrubber though.