Ceramic Metal Halide

I'm designing a new flowering cabinet and I've been looking into the best HPS lighting I could find. In my research I found an alternative to HPS called Ceramic Metal Halide. It's only produced in 400 Watts and below but is leaps and bounds beyond the High Pressure Sodium bulbs of old.
The CMH is a full spectrum bulb, whose spectrum can be seen in the attached product description. When compared to HPS it is clear that CMH has the better distribution and has the added benefit of not requiring switching between Veg and Flower. CMH also runs much cooler than HPS, and if we remember our High School Science, less heat at the same wattage means more in being converted to light and not being wasted heating the air.
The only negatives I have heard about CMH, besides not being available in higher wattages, is bulb life. When compared to the top of the line HPS the difference in hours is 4,000 hours. I grow in a Sea of Green so my full lighting time is 1 week at 18 hours and 8 weeks at 12 hours per day. That comes out to 126 hours for veg and 672 hours for flowering for a combines 798 or 800 hours for easy of calculations. At 800 hours per grow, 4,000 hours is a difference of 5 grows.
On the other hand the ease of not needing to switch bulbs, get a switchable ballast or set up a t5 rig for vegetative growth out weights the 5 grows difference.
If any of the RIU community has used CMH please feel free to post your opinions and results, +reps for good replies.

I remember when I first found out about these things, not too long ago actually. I was excited, thinking it a grand new discovery. They're not new, however, and with a bit of research I changed my mind about exploring these bulbs.

You'll have to do your own research to see if any of this is relevant with newer bulbs, or whatever, but this is a bit of what I remember:

1) CMH don't have nearly the same luminous output as HPS or even MH of equivalent watts. I think the numbers were about twice the electricity for half as much light, or something like that. Even though the spectrum was more in line with what plants want there was a great deal more loss of efficiency then HPS or MH.

2) Temperatures were not an equivalent exchange, as the reduced luminous output needs to be weighed against using more bulbs. Essentially, it seemed that a setup would require an additional booster fan to handle two lights instead of one, or the same exhaust system as an HPS would be needed, so no net benefit there.

3) At the time, digital ballasts were not an option with CMH bulbs.

4) I think I remember something about these bulbs being more prone to shatter, potentially damaging plants. Not sure if that was a credible source though.

EDIT: Btw, that chart you posted is not representative of total output, only spectrum ratios. Don't think CMH puts out more lights, it actually puts out less, just a more balanced spectrum. I was misled by that at first, saw similar charts by the CMH producers who seemed to label things in an odd manner on purpose.

I'm using these bulbs and having excellent results; Philips Master Color Retro White (4k). I'll put my current grow up against any 400W HPS grow any day of the week.

I think the reason there is confusion surrounding these bulbs is because all CMH are not the same. After doing my homework on Philips CMH I found all CMH are not the same. I would not trust any other brand calling themselves CMH

Measuring light in lumen's (what humans see) is antiquated. Have you ever seen LED's rated in lumen output? Plants see red and blue, and UV mostly.

Reguaring Philips Master Color Retro White (4k) CMH:

1. Puts out more red than HPS

2. Puts out more blue than MH

3. Puts out more UV than HPS/MH

4. Throws less heat...

5. Less Color Shift (less than 200k over their lifetime)

Warning:
NO DIGITAL BALLASTS - you will destroy the bulb. ONLY use a standard coil and core HPS ballast (dont let the name confuse you). CMH bulbs cannot handle the frequencies of digital ballasts. Of course there are exceptions to this rule as there is at least one digital ballast that is designed to work with CMH lamps. They are fairly expensive and unless you know you have one of these you don't so don't try. The Ceramic Metal Halide bulbs are positional. This means that they are designed to be EITHER horizontal or vertical (they cannot be used universally) but not both. Placing the bulb in the wrong position will cause it to fail early.

Thanks Cross, +rep as promised. Thats an important distinction, I'm going to run a test of HPS v CMH and should have accurate comparison by Dec-Jan at the latest.

What is the size profile of the cooler master ... will a 400w cmh accomidate a medium Adjust a wing with super spreader?

mh ballast, high ratted mogul socket... is that correct?

Green Cross said:

I'm using these bulbs and having excellent results; Philips Master Color Retro White (4k). I'll put my current grow up against any 400W HPS grow any day of the week.

I think the reason there is confusion surrounding these bulbs is because all CMH are not the same. After doing my homework on Philips CMH I found all CMH are not the same. I would not trust any other brand calling themselves CMH

Click to expand...

Good to know there's a specific bulb out there with real results. Bookmarked and +rep

granddaddykrush said:

What is the size profile of the cooler master ... will a 400w cmh accomidate a medium Adjust a wing with super spreader?

mh ballast, high ratted mogul socket... is that correct?

Click to expand...

The dimensions are:

It's about the same size as any normal 400 watt bulb so yes I'm sure it would fit that reflector.

The specs for the bulb, taken from the Brochure.

Thanks for the replies!

How does it compare spectrum wise to a 400watt HPS?

and is it worth going the extra mile for these opposed to convention grow lights (HPS/MH/t5)

EpicGear said:

How does it compare spectrum wise to a 400watt HPS?

and is it worth going the extra mile for these opposed to convention grow lights (HPS/MH/t5)

Click to expand...

Here are each of the spectrums, you be the judge:

EYE Hortilux Super HPS $92.95:


EYE Hortilux-Blue Metal Halide $99.99:


Phillips MasterColor Cermaic Metal Halide $55.95:

click here for a useful link from icmag.com. It's a stick in their Grow Room Design forum.

Great thread. I'm almost into the 4th week of flowering with these bulbs, and the buds are building nicely. See the results - to date - here My dual-400w CMH multistrain grow

Next grow I'll think I'll switch into HPS in the 3rd week of flowering just for comparison.

Good to know , thanks.
Great grow as well, GreenCross.

Yup, I am using one right now in my cabinet grow. I was using HPS so it was easy to change over. As far as Lumen's? I measured lumen's from my HPS at 18 inches and got 1200 I installed the cmh and got 1800 from the same distance.

I am in week 6 of flower and so far, very happy with the results.

Link to journal is in my Sig. Check it out if you like, I update regularly.

Im growing for the first time in a closet, using a 400watt cmh phillips, i started the plants with a 150hps for the first 2weeks, the 400watt cmh has made a huge difference they are about 2 1/2 ft tall and in flowering im growing 2 gdp, and 2 pineapple cush and idea on what kinda yeild the 400cmh puts out?? Thanks

cruzer101 said:

yup, i am using one right now in my cabinet grow. I was using hps so it was easy to change over. As far as lumen's? I measured lumen's from my hps at 18 inches and got 1200 i installed the cmh and got 1800 from the same distance.

I am in week 6 of flower and so far, very happy with the results.

Link to journal is in my sig. Check it out if you like, i update regularly.

Click to expand...

just goes to show how useful a light meter is, clears up a lot of debate about cmh or hps/mh. I'll be going with philips cmh my friends.