400W MH Lense Options

Hi all... As you can see I'm new to the the forums and have done my fair share of reading on here lately to setup my first grow. I won't be starting my grow till spring time as I live in Canada and where I'm going to be setting up the grow room isn't well insulated for winter growing at this time.

So my question to all you is about lighting, I can get my hands on some 400W MH fixtures real cheap $30/$40 for either including bulbs, one has a metallic lense and the other has an acrylic lense. Which one would be better?




Which would you recommend for my first grow?

I'd say go with the metallic one, you want the light reflected back onto your plants, the acrylic hood would allow it to diffuse away from them.
That said, if the bulb is hanging vertically as it looks to be, then you aren't getting the most from your bulb. The length of the bulb should be exposed to the plants, either horizontally above them with a reflector above itself, or suspended vertically in amongst the plants, sans reflector. It's the sides where light output is greatest, not the end.

Thanks for the input Hairy... Couldn't I also remove the lense, turn the fixture horizontal and make my own reflector to better diffuse the light from the sides of the bulb? Or say modify the exsting metallic lense (cut out a portion) and turn horizontal?

I don't see any reason why you couldn't do that, with a sheet of dimpled ally (A dimpled pattern will be better, as they produce balanced light footprints, the flat polished type can produce hot spots and uneven light distribution.) just make sure there's a small (1/2") v shape along the length of the reflector, directly above the bulb, this will prevent a major hotspot forming in that area.

I was reading some DIY reflector ideas today and I think I'm going to go with a bat wing style made out of some 8" 30GA galvanized vent. Basically unfold it, get my 1/2" crease in the center, weld a brace to prevent it from returning to its round shape, and paint it white with some high heat paint. I think that would be the most cost effective reflector. $5 for the vent and $10 for the paint. I should be able to mount that to the existing bracket on the fixture. I'll definitely have to start up a grow journal once I start purchasing the supplies.