Max wattage?

[xerhoss]

Hey, fellas...

I'm starting my first grow op with coco this weekend. Working with a 4X8 flower room with a 4" air intake duct at one end and 6" exhaust set up with 440 CFM inline fan on the other. I'm also fully ducted through a Cool Sun XL 8" hood running a 1000watt dual arc bulb (400 watt MH and 600 watt HPS).

I'm keeping it simple this time around with straight HydroFarm organic coco and Head's Method for daily hand watering (a coco-specific version of the Lucas Formula). The only additional supplement i'll be running is hygrozyme in addition to the 2 base nutes (which are GH Flora Micro and GH Flora Bloom) unless i run into issues.

The question i have is whether or not it would be feasible to use TWO 1000 watt bulbs with two XL 8" vented hoods in that 4X8 space with the 440 CFM fan for flowering or am i sure to run into heat/humidity issues given the size of the room?

Any experienced advice would be much appreciated.

 

[St3ve]

depending on the temp of the fresh air coming into the room I'd say no prob.

I've ran two 1k hoods on a 465CFM fan and could easily keep the temps around 77-78F. My fresh air coming in was a 18" square vent bringing in about 60F air.

 

[Widowmaker]

Tried running a single 1000w water cooled in a sealed 10x12 room with 6 plants. Humidity got to over 90%. Rented a commercial dehuey 60 pint a day unit. It got it down to 50% but raised the room temp about 6-7 degrees and used 500watts and was noisy. So I now vent the room just to remove humidity. I Do not grow in the summer because its too hot here in so cal. Hope that helps

 

[xerhoss]

depending on the temp of the fresh air coming into the room I'd say no prob.

I've ran two 1k hoods on a 465CFM fan and could easily keep the temps around 77-78F. My fresh air coming in was a 18" square vent bringing in about 60F air.

Good news, indeed...but what was the size of your room running the 2 hoods?

18" is a good sized intake. I was thinking maybe 6-8" intake tube ported through the wall and terminating inside the room directly behind an oscillating fan on the girls (so it doubles as a back draft damper as well - not that it would probably be an issue when the exhaust is running.

This is also an underground basement grow, so as you say, the incoming temps will be around 60-65.

 

[motherlode]

the one issue I see is having a 6" exhaust and only a 4" intake - your bottlenecking your fan

I run 2 6" intakes for my single 8" exhaust

 

[St3ve]

Good news, indeed...but what was the size of your room running the 2 hoods?

18" is a good sized intake. I was thinking maybe 6-8" intake tube ported through the wall and terminating inside the room directly behind an oscillating fan on the girls (so it doubles as a back draft damper as well - not that it would probably be an issue when the exhaust is running.

This is also an underground basement grow, so as you say, the incoming temps will be around 60-65.

Room size 8x8 but really just turning over the air is whats key.

HVAC codes call (on avg) for 12"x12" passive intake for every 300CFM of exhaust. (taking in to account elbows and anything else restricting the flow) If you have the room for it then the more the merrier. You really can't have enough fresh air IMO.

Right now I have a 465CFM and a 300 CFM with carbon filters in front of them and I still have a 24x18 fresh air intake. :) In a 12x8 space and 3000w my temps never get above 78F and humidity never over 45%. Best of luck..

 

[motherlode]

Room size 8x8 but really just turning over the air is whats key.

HVAC codes call (on avg) for 12"x12" passive intake for every 300CFM of exhaust. (taking in to account elbows and anything else restricting the flow) If you have the room for it then the more the merrier. You really can't have enough fresh air IMO.

Right now I have a 465CFM and a 300 CFM with carbon filters in front of them and I still have a 24x18 fresh air intake. :) In a 12x8 space and 3000w my temps never get above 78F and humidity never over 45%. Best of luck..

thats cool - learn something new everyday! I always thought I was working my fan a bit too hard

 

[xerhoss]

Thanks for the input, guys. :)

I went with a 10X10 intake on the ceiling (kitty corner from the filt/exhaust). It seems to be adequate for the space. I'm running a temp test right now in the room with a single 1000 watt dual arc running for 18 hrs.

From your input though it's sounding like i should have no problems adding the second hood, which is ultimately what i was hoping for since i'm not sure how well a single hood would spread light to each of the far walls (on the 8' run). 2 = 'mo betta.' :party0042:

 

[xerhoss]

On a side note, if need be, i can always cut in another intake hole on the other corner of the ceiling down the road.

 

[omk2teg]

is a 1000watt too much for a 3x4 grow space?

 

[St3ve]

is a 1000watt too much for a 3x4 grow space?

You just don't need it IMO. 600w would be great.

COULD you do it? Sure just gotta move plenty of air through it and the tent. I would run a 600w tho if it was me.

 

[jack_ripa]

I would go with 2 600s rather than 2 100s. True, you can do it and you will get more bud but is it worth the extra 800 watts in electricity? Probably not. There is a cutoff and overlap in the lights. In my opinion, 2X600 would be ideal for 4X8. If you had 5X10 I would say go for it, you would get 16 sq feet extra of ideal coverage. Just make sure if you go with the 2X1000 that you have good, downward reflecting hoods.

 

[jack_ripa]

You just don't need it IMO. 600w would be great.

COULD you do it? Sure just gotta move plenty of air through it and the tent. I would run a 600w tho if it was me.

Ditto. Optimizing the space is what we should all be going for. 600 is plenty for 3X4' IMO.

 

[strictlyOG]

is a 1000watt too much for a 3x4 grow space?

1000 watt would be perfect! my buddy ran a 1000 in a 3x3 and came out with some monster plants. his colas look like donkey di*cks!

 

[xerhoss]

On a side note, if need be, i can always cut in another intake hole on the other corner of the ceiling down the road.

Yep...had to do it after all. I enlarged the first one to a 10 X 12 and cut in another 10 X 12 in the other corner of the ceiling. Much better air flow!

The girls are growing up a bit and looking like they might be getting close to ready to hit the big light.

Thanks again for your suggestions, fellas. :)

 

[xerhoss]

I would go with 2 600s rather than 2 100s. True, you can do it and you will get more bud but is it worth the extra 800 watts in electricity? Probably not. There is a cutoff and overlap in the lights. In my opinion, 2X600 would be ideal for 4X8. If you had 5X10 I would say go for it, you would get 16 sq feet extra of ideal coverage. Just make sure if you go with the 2X1000 that you have good, downward reflecting hoods.

I'm running the cool sun XL 8" vented hoods by sun system. Fingers are crossed. I'll probably run a temp test before putting the girls in veg in case i have trouble controlling the temps even with the current air supply.