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Ceramic Metal Halide (CMH)

I've been thinking about a CMH for my vegetating area. Would a 250 watt be sufficient for a 4x2 tent (8 sq ft)?

I'm using a 250w for 3x2' area in a cab and I'm not sure it'll be enough. However, I want to veg quicker so throwing more light in should help if all else is good and also for flowering.

So, probably depends on how long you plan to veg for and how much you want to yield.

I'm probably going to add a 150w cmh to my 250w hps-retro white, should give excellent results.
 

njrmutcd

Member
Hmm. I don't really care too much about speed (since their mothers will be flowering for 8-10 weeks anyway), but I'm concerned about stretching if there isn't enough light to go around.
 

guanito

Active member
Just to let you guys know - my CMH just shit the bed after 5 1/2 years.
It was manufactured in 2007 and I've used it constantly since then. Lucky I had a spare which I purchased at the same time. Now I need another.

best regards
 
Hmm. I don't really care too much about speed (since their mothers will be flowering for 8-10 weeks anyway), but I'm concerned about stretching if there isn't enough light to go around.

Personally, I'd go for more like 400w if I was you. I've yet to use one of these setups, though... So hopefully someone more knowledge will chime in and give their advice. I've just been on the side of too little light too many times now because I under estimated things.
 
U

unthing

one more thing. does anybody have pics or knows what happens to those double glassed "open rated" cdms at bulb failure? does the glass contain the explosion or not? i just think that to be able to run them without closed hoods would give more versatility of application.
 
I've seen a pic of Philips retro white that blew and the glass contained it. From what I've learned, Philips is the most trusted when it comes to running open fixture. If they say it's open fixture rated it is and it won't breach the outer glass.
 

Ranger

Member
one more thing. does anybody have pics or knows what happens to those double glassed "open rated" cdms at bulb failure? does the glass contain the explosion or not? i just think that to be able to run them without closed hoods would give more versatility of application.

i had one go on me but it wasn't an explosion, just a fracture in the ceramic connector and poof it died without drama.
 

njrmutcd

Member
I've never wired up a ballast or anything before. I see those Philips ballast kits for $69. They come with instructions to wire them. I've never done that before but it looks easy enough. Is there a housing or something that I need to get as well?
 

Anti

Sorcerer's Apprentice
Veteran
I considered building a ballast kit. I wired my own room, afterall. Then I thought twice about it and spent the extra $100 on a ballast that comes with a warranty and required 5 minutes between unpacking and use.

5g-7g to pay for the difference. My time is better spent growing than tinkering with ballasts.

YMMV.
 

rives

Inveterate Tinkerer
Mentor
ICMag Donor
Veteran
28 days with the CDMs. I'll try to get better pictures after lights out - I can't believe that I can get better pictures under leds/fluorescents than I can these, but..... They are so goddamn bright that I turned them down to 50% for these pictures and they were still washing out. Need more experience with it.

In the second picture, that bud is about 4" long. I think that the onset of flowering started a couple of days later with these than my hybrid fixture, but if this continues, it looks like the buds are going to be substantially bigger.

picture.php


picture.php
 

njrmutcd

Member
I considered building a ballast kit. I wired my own room, afterall. Then I thought twice about it and spent the extra $100 on a ballast that comes with a warranty and required 5 minutes between unpacking and use.

5g-7g to pay for the difference. My time is better spent growing than tinkering with ballasts.

YMMV.

In my case, that $100 is a pretty huge barrier. My time is cheap.
 

fungzyme

Active member
one more thing. does anybody have pics or knows what happens to those double glassed "open rated" cdms at bulb failure? does the glass contain the explosion or not? i just think that to be able to run them without closed hoods would give more versatility of application.

The picture I've seen was at the advanced tech lighting page.
Here's a link - it's at the bottom of the cmh fact page:

http://advancedtechlighting.com/cmhfact3.htm
 

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