Quote Originally Posted by MaryLane
Ahh cool. Sounds like a nice set up.

I am trying to decide if I want to throw my CMH 400w in a DIY bake a round cooltube or leave it open. I am doing a barrel style vscrog so the distance to the plants is fixed. Right now I am planning on a 20" diameter screen, which puts the radius at 10". I think I amy do the cooltube and reduce the diameter to maybe 18" or so.

What do you think? I will have plenty of ventilation either way, and my ambients never go above 75F, usually staying around 71F.
Hi.

I'm not a light expert or anything, but these bulbs are rated for open fixtures. They have X-amount of Uv block built into the glass bulb. If you need to use a cool tube, select the proper kind of glass tube or you will block too much of the Uv light; which the plants love.

A fixed light distance; is a over-my-head growing style. I adjust my light distance daily......and scrog is too. I just let them puppies grow. I have plenty of height distance to work with.

Bottomline: Everbody's grow room is different, so I usually avoid giving advice, but the key is to test everything in advance, I think. Keep temps between light and top of plants around 75-80 degrees; with good air circulation, that is good common advice....enjoy!
Dutch Pimp Reviewed by Dutch Pimp on . Ceramic Metal Halide Bulbs...for HPS ballasts? Phlips MasterColor Ceramic Metal Halide ~ CMH ~ HPS-Retro White OK..techies...what does everyone think about this bulb? Rating: 5