[timmur]

Originally Posted by pulverizer

Newbie lurker here - just ordered a single GB 315 unit from GH with the 4200K for my new garden and am planning to run just one in a 4x4 tent. Intend on using the 942 bulb for both veg and flowering. Do you guys think I am being overly-optimistic thinking this single light will get me a decent yield? This is my first attempt at growing ever, but after doing lots of research I wanted to get something that will give me good results and is energy efficient. I would really be happy with any yield (not killing the plants would be a win!).

All my parts are on order and I am setting up a RDWC system over the next week or so.

Thanks everyone for the awesome info in this thread already. Really helped my decision to pickup the GB unit as opposed to cheaper nanolux/sunsystems/phantom setups.

I'd run two in a 4 x 4. One will get it done in a 3 x 3.

[timmur]

So I just got the real modeling back from Cycloptics (not their approximation) and holy crap the PPFD is higher than I planned on! Here's the model.



Here's what Flip had to say about the unique arrangement of the lights:

Here is modeling for your 12 Greenbeams 4200K luminaires in your 8x8x8H room. The optimal uniformity on both planes is achieved using the uniform, radial installation template.
The modeled Avg/Min and Max/Min uniformity at 12” above the floor is very light at 1.04 and 1.08 respectively with estimated average irradiance of 841 umol/m2/s. The wall to wall uniformity on the second plane 12” (only) below the apertures holds up very well with modeled average irradiance of 1369 umol/m2/s.

An interesting feature of the radial installation pattern, and 360-degree uniform radial beam distribution pattern of Greenbeams, is that you can proportionally reduce the average irradiance by 50%, 33%, or 25% , with minimal impact on uniformity, by turning off every second, third or fourth Here is modeling for your 12 Greenbeams 4200K luminaires in your 8x8x8H room. The optimal uniformity on both planes is achieved using the uniform, radial installation template.
The modeled Avg/Min and Max/Min uniformity at 12” above the floor is very light at 1.04 and 1.08 respectively with estimated average irradiance of 841 umol/m2/s. The wall to wall uniformity on the second plane 12” (only) below the apertures holds up very well with modeled average irradiance of 1369 umol/m2/s.

An interesting feature of the radial installation pattern, and 360-degree uniform radial beam distribution pattern of Greenbeams, is that you can proportionally reduce the average irradiance by 50%, 33%, or 25% , with minimal impact on uniformity, by turning off every second, third or fourth luminaire.

If I go with this arrangement then I'll certainly only run them for 10 to 11 hours during flower to keep the DLI down to a reasonable level. This actually works well as I'll be running pure sativas from Ace which want the longer nights.

BTW, the Greenbeams deliver on Thursday!

[Scrappy-doo]

One would be perfect in a 4x4 imo. If I wanted to run 2 I'd get a 2nd tent.

[timmur]

Originally Posted by Scrappy-doo

One would be perfect in a 4x4 imo. If I wanted to run 2 I'd get a 2nd tent.

You should probably listen to this guy as he's already done it very successfully!

You can always add a second light if you don't like results!

[pulverizer]

Thanks Scrappy and Timmur. Will be documenting my grow here once it starts - we will see how it works!

[Ez Rider]

Just heard about these units from rives. I'm currently running (2) water-cooled 1000wHPS in my 5x9 tent, and the power bill is killing me. I'm almost finished with my current run, and I'll be switching to C/G's for my next run. I'm going to run 4 in my 5x9, and see how it goes. I'm watching this thread with interest, and should be a regular contributor once I've got the light switched out...hopefully next week. I've been averaging 2.5# with the 1K's(sour bubble), hoping for the same or better.

[Scrappy-doo]

I think you're going to be very happy with that decision Ez. Very close to my setup.

[MangoCat]

I'm running 4 GB's in a 4' X 8' Gorilla tent. The actual canopy top is 4' X 6' with 2' on one end for fan and filter. I couldn't be happier with the intensity and uniformity. 5' X 9' may be a bit of a stretch for 4 GB's; but it'd be easy to throw a couple more in there if need be. You'd easily reach your 2.5#, more I'd bet

[Ez Rider]

Originally Posted by Scrappy-doo

I think you're going to be very happy with that decision Ez. Very close to my setup.

Originally Posted by MangoCat

I'm running 4 GB's in a 4' X 8' Gorilla tent. The actual canopy top is 4' X 6' with 2' on one end for fan and filter. I couldn't be happier with the intensity and uniformity. 5' X 9' may be a bit of a stretch for 4 GB's; but it'd be easy to throw a couple more in there if need be. You'd easily reach your 2.5#, more I'd bet

Thanks for the input

What can you guys tell me about heat output from the C/G's? My tent sits in a large, well ventilated room, which I air condition in the summer months. The actual room rarely gets over 75F(I turn on the a/c if it does), and my current water-cooled set -up makes the tent run ~3F hotter than the actual room temp. I'm planning on using 2-6"maxfans with carbon filters for exhaust, and 2 more maxfans set on medium with filters for intake. I figure on moving 500-600cfm through the tent, with oscillators on each end to keep air moving under the hoods. Does this sound reasonable? Flip say's 4 C/G's will put out 3000btu's and 6 will put out 4500. That's about 2.4btu/w. The rule of thumb I've always seen used is 3.16btu/w for traditional mh/hps. Do these lamps really run that much cooler? When I use the standard 3.16btu/w, I come up with ~4000btu/h with 4 C/G's, and ~6000btu/h with 6. I can move enough air through the tent to comfortably cool 4000btu/h, but trying to do 6000 could prove impractical. See chart:https://https://docs.engineeringtoolbo...air_volume.pdf

I'm still on the fence about needing 4 or 6, and the #'s flip sent me are confusing. I'm going to try to get some clarification from him, and hoping for some input from the community as well.

One important point. My tent is a 5' x 9' model. However, the negative pressure from the exhaust collapses the sides and ends. The true inside dimension is more like 4' x 8'.

Anyways, I'm going to go over the figures Flip sent me, and try to make some sense of it. I'll be back if I do...

[McKush]

Originally Posted by Ez Rider

Just heard about these units from rives. I'm currently running (2) water-cooled 1000wHPS in my 5x9 tent, and the power bill is killing me. I'm almost finished with my current run, and I'll be switching to C/G's for my next run. I'm going to run 4 in my 5x9, and see how it goes. I'm watching this thread with interest, and should be a regular contributor once I've got the light switched out...hopefully next week. I've been averaging 2.5# with the 1K's(sour bubble), hoping for the same or better.

Hey EZ - i agree with mangocat. Youll need more fixturs to match those 2 1000s as far as umol/m2s goes. You are prob around 800+ with your current setup and your 4 GBs will put you around 530. Less heat for sure but 700-800 is an often used guideline for flower. Those are rough numbers but you may want to adjust. I recommend contacting them for a room design i believe it is free of charge but never have tried

All the best with your room chap