LED Grow Light Forum

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If you go with more plants they'll fill the screen faster so you can switch to 12/12 faster.

2 x SS400w won't properly cover 4x8 but you did say you were downsizing so you know yield will suffer too. Start a journal and we'll try to help you out...if you want.


SME

SME, I attached a drawing to try to better illustrate what I am trying to achieve. Although I would like to keep the grow purely LED based on what I've read and seen I'll probably need to add a few CFL's to achieve acceptable lighting as the grow progresses. I already have the fixtures since I will be cloning so it would be simply a matter of hanging the lights.

*Edit*
The 1' blue section in the front is a walkway. (I added it so I could service equipment and trim with ease)

Unless anyone has any tips on a better way to organize the room I'll be starting the grow in the next week or 2 once I cut and root clones. I was just informed of when I should receive the light and even if I took the clones tonight the light will be here before I can use it. I was hesitant to clone earlier since others mentioned a longer wait but the whole process from initial contact to receiving the light will have only taken a week and a half. (One person mentioned it took them 3 months.)

Your plan will work but I'm not sure about all of it.

With the SS400w lights a 3x3.25 area (each) is too big, imho. You'd probably want more like a 2x3 area for each light so you could use a 4x3 area on one end of the tent for plants or you could run a 2x6 area along one of the long sides of your tent.

If you're supplementing CO2, keep the air pump out of the tent and don't run exhaust or the carbon scrubber while the lights are on either. No sense in wasting your CO2.

SME the carbon scrubber is recirculating the tent never vents. CO2 cost too much to throw straight outside.
From the get go I felt the amount of light was a bit low.. My goal this grow is to not use the AC only the ice box. By my calculation with cfl's I'd be up to ~53W/sf

The carbon scrubber scrubs the carbon off of CO2, if you run it while the CO2 is there you're not just wasting the CO2, you're wearing out your carbon filter quicker too.

I'd skip the cfl's altogether and make the space smaller (or get another real light) but that's just me...

SME
I was looking at your advice and decided to do a test. I think for this grow I'll leave the scrubber in the tent but I'll try having the air pump outside of the tent. I know in high CO2 environments CO2 causes pH issues with the water in past grows relocating the air pump was not an option since I didn't have a tent.

The first test lasted 8 hours during the test I had the CO2 generator fill the room than once it cut off I recorded the CO2 PPM.

Test #1 Tent only - It over shot to 2035 PPM 8 hours later I recorded it at 1950PPM.
Test #2 Tent + carbon scrubber- starting 1945PPM 8 hours later recorded 1820PPM.
Test #3 Tent + carbon scrubber + Air pump outside tent- starting 1800PPM 8 hours later 750PPM.

It seems like the carbon scrubber does result in CO2 losses but it seems to me that the losses are more likely from the tent leaks than actually removing the carbon.
According to my research activated carbon is a horrible CO2 filter since it quickly becomes saturated with CO2 and when the CO2 levels fall it releases the CO2 back into the air.
I also attached a pictures of a PDF that was readily available from a company which deals almost exclusively in industrial applications and it seems the adsorption rate of the filter would be negligible at best.

Having delved deeper into the subject of a carbon based air scrubber vs scrubbing carbon from air led me to find that completely different chemicals are used in the process of actually removing carbon from the air. (Sodium Hydroxide or Calcium Oxide seem to be popular carbon removers.)

Interesting. I knew that the carbon would absorb CO2 but I didn't know it releases it back once the levels drop. I wonder how much less the odor control works if the carbon is already saturated with CO2? I still think it's best to not run it (or not much) while CO2 is being supplemented but maybe it's less of a problem than I thought.

Update:
Clones are heavily rooted I'll start a SS400 GFP Journal when I get the chance to set up the buckets in the room and transplant.. I'll be tinkering with water pumps and timers since i haven't run this setup so small.