Ceramic Metal Halide (CMH)

[KosmoKramer]

After 4 years its finally time to step away from old reliable. Been waiting years for Phillips to put out a higher wattage CMH to no avail.

Making the switch/upgrade to a 600w digital ballast and a mixture of bulbs. Seems like early flowering with MH, mid flower HPS, and finishing with MH gives the same if not better quality results as the CMH.

Love the CMH, don't get me wrong, just way too much work to get bigger yields out of it.

 

[Ty_Kaycha]

...Seems like early flowering with MH, mid flower HPS, and finishing with MH gives the same if not better quality results as the CMH.

Love the CMH, don't get me wrong, just way too much work to get bigger yields out of it.

Umm I'm confused. Too much work to use 1 CMH bulb or too much work to keep switching bulbs every few weeks?

 

[growshopfrank]

Umm I'm confused. Too much work to use 1 CMH bulb or too much work to keep switching bulbs every few weeks?

probably too much work training plants to work with the limited light penetration that comes with using 400w fixtures.

 

[Ty_Kaycha]

I run bare bulb, and it's pretty damn easy moving the light up & down. But to each his own.

 

[statusquo]

if you are unsure which socket to get go with the horizontal socket as it will work with both lamps
whatever you do do not operate a position oriented lamp in other than its designated orientation as you will greatly reduce its life and with some lamps it can be dangerous.

So if I have a 400 watt HPS ballast with a HTG (high tech garden) reflector + horizontal 400W CMH can I just take the socket out of the reflector and purchase new vertical bulbs?

 

[Baba Ku]

Yes, there is no such thing as vert or hor sockets. They are universal save for size. We use medium sockets for CFLs, regular incadescent bulbs, and small HID's like 150's. Most all other HID lamps will use a Mogul size socket. Again, the positioning of the socket is not a factor at all. Only the bulb orientation matters.
Taking a lamp more than 15degrees out of the horizontal plane for hor lamps can cause the polarization of the lamp to be off. This can reduce the total life of the lamp.
Thing is...we should probably be changing out the lamps before the total life of the lamp is realized. Even though an HID is still lighting and doing it's thing, they loose effectiveness with age.

Now, the CMH is a different animal than most HPS lamps. It has a special patent that covers the technology used to fire the salts. I cannot say for sure, but I read the patent for the lamps that Philips has, and I am fairly certain I remember that one of the key parts of the patent is that the bulb can be run in either orientation without a different type of mechanics. I think it was one of the key points of it being patentable.
It goes against that theory since they do indeed sell bulbs with the distinction of orientation, but I am pretty sure that there is no need to worry about position with the Philips CMH in 250 and 400 watt sizes.

 

[Maj.Cottonmouth]

These are 400w ballasts and sockets from HTG, I just stripped the reflectors off and added the chains to hang them from

 

[Aerohead]

Baba Ku, nice post I believe you are right.

I have been using a Hor 400w CMH in a vertical position for over a month, so far, all is good. Bulb fires right up, burns very bright, no issues. I am willing to accept a shorter life from the bulb as I don't use them for more than two grows.

I have switched to vert grows and had a brand new bulb in the box and didn't see the point of leaving it in storage and not using it at all. I will replace it with the proper bulb when the time comes, I will keep everyone updated on the bulb life but I don't plan to run it past 2 harvests anyway, lets see it it makes it....

 

[lamsbread]

help. what colour/kelvin CMH do i need?

help. what colour/kelvin CMH do i need?

Hi i am looking for some advice. i live in the uk and cant find the "philip's retro white 250w". I've been looking all over and have eventually found a place that does 150w cmh , which are also open fixture. The problem is that they come in different "colours (kelvin)" what colour is best. If you want i can supply the web address (wasn't sure if i can do this eg. forum rules etc).

 

[lamsbread]

Orientation of bulbs = Highbay lamps are vertical. Lowbay horizontal. This is not always the case, sometimes Lowbay are also vertical but as a rule Highbays are pretty much always vertical.

 

[Baba Ku]

Any HPS lamp can be used in any orientation and it makes no difference.
Only metal halide lamps consider the orientation of the lamp. Some it may be due to a safety issue where the protection apparatus is different for each orientation. This is not the case with the CMH lamp.

Some metal halides have their polarity "tuned" for optimum function in either one position or the other. The result of running a position tuned halide lamp in the wrong orientation is less than optimum lumens and temperature. The difference would probably not be detectable without sensing equipment. It could also mean a less than optimum lamp life..but the difference between a full life bulb, and one that was shorter due to being run in another orientation, would both be much longer time than we should keep the lamp in service. So it makes the issue moot really. Unless you are trying to get 3.4 years out of a lamp instead of just 3 years, then you can run the CMH in either hor or vert.

That is not to say that you don't give yourself the best shot by using them as prescribed, because you probably do.

 

[lamsbread]

yes i agree HPS & CMH orientation does not matter which orientation you choose. As for MH they operate in a vertical +/-15 position. When operated in positions other than +/- 15 degree of vertical,lamp wattage,lumen output and life will decrease; the arc bends, creating non-uniform heating of the arc tube wall, resulting in less efficient operation and shorter life.There are also bulbs "Universal Metal Halide" made to operate in the horizontal or any other position +/- 10 degree . These have HOR stamped on the crown or base. HOR = Horizontal.

 

[lamsbread]

Have you had any experience with "High Pressure Metal Halide" HPMH, Baba? as this is something i have only recently come across and would like to know more about.

 

[growshopfrank]

Its rarely a good idea to go against manufactures recommendations when you are using a product for its intended purpose. with a regular MH position oriented lamp if you go more than 15 degrees off its intended orientation there is a risk of arc tube failure. think of white hot glass flying around your room. (yes I know this isn't likely with a CMH )

The internal difference between a universal position MH and a horizontal MH is the arc tube is symmetrical on the U lamp while the HOR lamps tube is asymmetrical. take a look at a HOR. lamp the arc tube looks almost like a canoe,pinched up at both ends while the U. lamp the arc tube ends are cone shaped.
Not only do HOR. lamps need to be horizontal they also need to be clocked (rotated to) the right position(the little nipple on the arc tube needs to be at 12 o'clock)

 

[Azeotrope]

To be completely accurate on the position specific sockets, there are horizontal and vertical sockets. That being said it was that in years past the "super" metal halides AKA high output horizontals were keyed or had a tab on the male threads that would not allow them to fully penetrate a standard mogul socket. A standard vertical or horizontal bulb would work in the socket as well. They were made (and I think still are) to accomidate these Horizontal only high output halides. I suffered the inconvenience of purchasing one of the bulbs and going back the next day to buy the corresponding socket.

 

[duddits]

I was asked to post this for simba, hope this works!!

 

[growshopfrank]

here's a image of a POMB or horizontal socket these are yellow where a regular mogul is white notice the hook in the steel threaded part. to install one of these correctly mount it with the little notch in the porcelain facing up.

 

[joesmithjoe]

Why hasn't anyone posted about the new MH conversion bulbs that are now available?

Works with both pulse AND probe start.

http://advancedtechlighting.com/cdmallstart.htm

 

[Baba Ku]

If you only had a metal halide ballast (pulse or probe start) it may work out. Other than that, it does NOT have the light throw of the CMH and it is more expensive. For what? A huge lamp that can't be run in many tubes, and creates lots more heat than other lamps?
Very few people even run MH ballasts these days.

 

[joesmithjoe]

Well thats one way to look at it.

The other way would be to recognize that there are people with MH ballasts who may want to try CMH without having to buy a HPS ballast. The light spectrum is very similar to the HPS conversion bulbs and it costs a whole lot less then buying a new ballast + bulb.