Adding Another Bulb to a Cool Tube

I want to turn my Cool Tube into a Dual cool Tube. The one bulb that is currently in there is way off to one side, and there is room to add another fixture to the other end if I just drill the metal and add an extra fixture. This will leave the ends of the bulbs about 3 inches apart. Is there any reason not to do this? The two bulb Growzilla is about 200 bucks in a catalog. I could probably just sell my tube for a 100 bucks and get the new one, but I have an electrical engineering roommate who says he would do the work, no problem. Besides the risk of breaking the glass while drilling the metal at the end of the tube, is there any significant risk of overheating both the bulbs, or something else funky happening? The bulbs in the Growzilla, are parrellel to each other and several inches apart also. I would assume that the heat that they produce effects each other more then my planned setup.

Thanks in advance.

As long as you have enough air flowing through to pull the heat out its fine, but what happens if your extractor fan stops working one day?

Doesn't efficacy drop when lamps are too close together?

Im not sure what efficacy is. Please en-lighten me! hahahhahahahha! I think if the fan stopped, either way the other 600 watter is going to do interesting things. Im just looking at a tent temp of 77º with the fan barely on half power. I have a 6 inch Vortex. I could probably crank that baby up, and still keep a second burning, maybe not in the summer, but Sept-late May would be cool enough here at 7000 ft. I'm in a 4 X 4 X 6.5ft tent. The single 600 is doing a good job though, giving me all I can consume, I don't want to grow more then just what I can smoke, or make edibles from anyway. Not worth the hassle. Not sure why in the world I would even want to go with more light. Just had a wake and bake moment I guess. That's what happens when Im out of coffee and have to drink Yerba Maté

if you check out the post " 4x4x7 tent growers must click" that i posted a couple days ago under grow room setup youll see pix of my dual cool tube i run 600s in mine with temps at 77 but im prob gonna only run 2 400s in there in the summer and on lights out run my lil dr 120 with a 400 to keep shit steady... so 2 600s in the winter and 3 400s in the summer i feel ya bro all my shits personal too. i smoke like a chimeny lol

electronug said:

Doesn't efficacy drop when lamps are too close together?

Click to expand...

Its possible. I would study up a bit on 'wave interference' before putting 2 HID bulbs too close together.

Newtons theory vs Huygens theory started it all and then there was Thomas Young who actually discovered wave interference and disproved Newtons 'corpuscular theory'...

Wouldnt photons being both particles and waves lessen wave interference, then?

I believe thats what Newton first thought when he came up with the corpuscular theory...its been some time since I have studied it. But its very interesting stuff with alot of practical experiments you can do at home. Thomas Youngs work is the place to start looking....