HPS, MH, Floros, Phillips Cermamic Metal Halide has 'em all beat.

ThatOneDude said:

ceestyle, eariler you asked why someone would switch back to a cmh blub at the end of flower. I've read about a few people doing this and it's a split discusion at this point. The thinking behind it is that becasue the CMH bulb puts out UVB light that it will force the plant into protecting itself againt it by producing more thrics. Again, that's something that is split at this point and honestly I haven't been following it much anymore.

At this point there are plenty of grows that have gone through using CMH and from what I've seen it's coming out even as far as yeild, people say they end up with a more leafy bud and more thrics. I'm talking about grows where people have run the same strain over and over again, then switched to CMH, some go back to HPS some say the never will. To each their own.

Nobody I've seen yet has said they were going back to an MH bulb for veg. I'm using 1000 watts for flower and the 400 watt cmh for veg in a cab.

Click to expand...

Thanks for the info. Ya know, I really wish these people would run these comparisons side-by-side, because I have a hard time believing anything else. There are so many variables and all the measurables are subjective, when using memory recall to determine how frosty one is to compare to how frosty one was under different conditions.

It would be very very simple to supplement half your plants with UVB, while all were still under one HPS. This would be meaningful.

On the other hand, if someone grows the same number of plants and the same strain enough times to have a consistent yield - regular enough to establish some standard deviation - then growing CMH and finding that the yield is greater by an amount that is statistically significant would also be meaningful.

Otherwise, to me it is all anecdotal. I have heard so many swear that "xyz makes my bud so much better" .. when xyz is anything ranging from doing a rain dance to taking a crap the morning before harvest and not wiping that I don't believe much but straight up evidence that noone has to interpret for me. Call me a skeptic.

Where are these people that you speak of who use CMH and report the results? I have seen nothing here yet except speculation.

This is not my own personal info. It's just info available out there on the Internet. However, it's the closest thing to a side-by-side comparo I've run across. There's no complete division of light, but it reads honest to me [shrug]. International Cannagraphic Magazine Forums - C99xHaze Scrog

Picture and quote from the grower:

...I can't say that my final verdict was that clear. I couldn't tell the difference visually or in the quality of the bud between the CMH and the EYE HPS. For some reason the plants under the CMH stretched more during flower (though all plants grew tight nodes during veg under the CMH). All in all both lights gave me equal results in the end. If i had to choose between one of the two i would choose the CMH, if only because the plants look much more natural to me under the CMH than the HPS...

Click to expand...

Hawk said:

This is not my own personal info. It's just info available out there on the Internet. However, it's the closest thing to a side-by-side comparo I've run across. There's no complete division of light, but it reads honest to me [shrug]. International Cannagraphic Magazine Forums - C99xHaze Scrog

Picture and quote from the grower:

Click to expand...

Thanks for the post. That's really surprising.

Another quote from the grower:

I try to be a scientific observer when it comes things such as the CMH vs. HPS debate. Saying that, i did not really design my grow in a way that accurately compared the CMH vs. the HPS. I used the CMH for veg, then moved plants around 5 days into flower when i put in the SCROG Screen. Also I had different reflectors on each light. Basically what i'm trying to say is that while my observations were made carefully, my lack of forethought in these matters means that my findings need to be taken with a large grain of salt.
Anyway enough of that....i say buy the CMH if you already have a magnetic ballast, and see how it works for you. Definitely worth the $50.
I digress...

Click to expand...

It's surprising enough to me that they're comparable, considering how much lighter in red the CMH is.

So the general consensus so far is that CMH is better than MH for veg but it's "undecided" vs. HPS in the flowering stages?

No. CMH is better than MH conversion. I don't think it was decided that it was better than MH.

We have one grower who stated that in an imperfect experiment, his judgment - not a measurable - was incapable of detecting a difference in bud quality. It was not quantified in any way.

Thanks ceestyle. I trust your judgment so I think I'll pick up a CMH to replace my MH conversion once it craps out.

Guys you need to understand that these bulbs should be used by a closet grower. One bulb from start to finish no need to buy a conversion bulb, or multiple ballasts/light systems. That is one of the main focuses for growers IMO, that and spectrum are primary reasons for purchase.

mdgcmd said:

Guys you need to understand that these bulbs should be used by a closet grower. One bulb from start to finish no need to buy a conversion bulb, or multiple ballasts/light systems. That is one of the main focuses for growers IMO, that and spectrum are primary reasons for purchase.

Click to expand...

If I have an HPS ballast, I would not use a CMH bulb instead of HPS for flowering. I would consider one instead of a conversion bulb, although there are some good ones out there. I think most people would fit in this category.

For $50, is'nt it worth giving it a try to see for yourself?

ThatOneDude said:

For $50, is'nt it worth giving it a try to see for yourself?

Click to expand...

For veg, yes. If you're totally happy with what HPS does flowering and there is nothing to suggest that CMH would be better - including the numbers - I would only consider it for a side-by-side on a small scale.

Does these work with digital ballasts?

Psilocobe said:

Does these work with digital ballasts?

Click to expand...

I *heard* no. But the bulbs are kinda pricey. For the money (especially for a digi ballast) better off buying 2 bulbs, a true MH and true HPS. (if using the same fixture to veg and flower)

My main interest in the ceramic MH is the heat. If I can really grab it, its worth looking into.

BigBudBalls said:

I *heard* no. But the bulbs are kinda pricey. For the money (especially for a digi ballast) better off buying 2 bulbs, a true MH and true HPS. (if using the same fixture to veg and flower)

My main interest in the ceramic MH is the heat. If I can really grab it, its worth looking into.

Click to expand...

you are correct.

ceestyle said:

you are correct.

Click to expand...

Great minds think alike? (even us, too! )

CMH is a much better growing lamp than a Metal Halide because it produces
much more PLANT LUMENS per watt, and is still very rich in blue and violet that will keep the plants stocky and bushy. The spectrum is just like the sun and you will get results just like you're growing in an open field WITH THE SUN SHINING FULL 24/7!!! HPS have even more plant lumens per watt, and even though it is deficient in blue, by that time the plant has switched its metabolism over to putting on the weight, so HPS works better with flowering.

object16 said:

CMH is a much better growing lamp than a Metal Halide because it produces
much more PLANT LUMENS per watt, and is still very rich in blue and violet that will keep the plants stocky and bushy. The spectrum is just like the sun and you will get results just like you're growing in an open field WITH THE SUN SHINING FULL 24/7!!! HPS have even more plant lumens per watt, and even though it is deficient in blue, by that time the plant has switched its metabolism over to putting on the weight, so HPS works better with flowering.

Click to expand...

Show me the data. I'd like to see it.

Trying to learn all I can about lighting and been through 15 pages of this thread and am stumped. A few questions:

1) Was there any agreement eventually that a CMH is a good or better alternative to MH alone or combined with an HPS as opposed to MH/HPS combined? I take it there's no agreement at this point which is why the thread is still going.

2) I was aware one of the issues with MH is heat. But I know there are ways to vent the lamp and thought that's what people do and that it works fine. I was thinking you could get an MH around 12" from the canopy if it's vented/cooled which seems close enough. Is that about right? Can/does a CMH produce as much full spectrum and enery with much less heat than the Hortilux "blue"? EYE Hortilux BLUE

3) Does the Hortilux Super HPS have more than enough "blue" for vegging yet still run a lot cooler than MH or CMH? At 80,000 lumens if so, it would seem simpler for me at this point and only one bulb to think about. EYE Hortilux Super HPS

4) It sounded like some people are not sold on digital ballasts over magnetic for MH and or HPS. Which type of ballast would you get with MH or HPS?

VirginHarvester said:

Trying to learn all I can about lighting and been through 15 pages of this thread and am stumped. A few questions:

1) Was there any agreement eventually that a CMH is a good or better alternative to MH alone or combined with an HPS as opposed to MH/HPS combined? I take it there's no agreement at this point which is why the thread is still going.

Click to expand...

No, there's no agreement. I'm not saying it's not the case; I just haven't seen any data that shows it's so. All I hear are hand-waving or intuitive arguments. I just want to see data ...

That said, I'm pretty sure that if you get an HPS ballast, you are better off with a CMH for veg than with a MH conversion bulb.

2) I was aware one of the issues with MH is heat. But I know there are ways to vent the lamp and thought that's what people do and that it works fine. I was thinking you could get an MH around 12" from the canopy if it's vented/cooled which seems close enough. Is that about right? Can/does a CMH produce as much full spectrum and enery with much less heat than the Hortilux "blue"? EYE Hortilux BLUE

Click to expand...

The Blue runs on a MH ballast, whereas the CMH runs on a HPS ballast. Unless you're going to get two ballasts straight away - which from your other thread I gather you are not - you are going to get an HPS ballast. Then just decide whether you have the cash for a CMH instead of a MH conversion.

Heat is an issue, but:

1. I have yet to see anything detailed about the heat that a CMH puts out. I will probably pick one up and check it out, and post some results.

2. You are still going to have to deal with heat with an HPS bulb anyway, so I wouldn't base your decision based on that. You haven't said anything about your grow area situation, but it's really not that hard to work around. Fan+duct+cooled fixture=manageable heat.

The distance from the canopy will depend on the size of bulb you are using, but 12" is probably a bit close unless you're using something a bit smaller like a 250W. You also reduce coverage area when you have your light that close.

3) Does the Hortilux Super HPS have more than enough "blue" for vegging yet still run a lot cooler than MH or CMH? At 80,000 lumens if so, it would seem simpler for me at this point and only one bulb to think about. EYE Hortilux Super HPS

Click to expand...

That's a good single bulb, but the heat issues will be roughly the same as a MH or HPS. You can get away with just an HPS and no MH if you want - many people do - but the extra blue sure couldn't hurt.

4) It sounded like some people are not sold on digital ballasts over magnetic for MH and or HPS. Which type of ballast would you get with MH or HPS?

Click to expand...

For HPS, I would go with the magnetic, as you need it should you decide to get a CMH. I have heard there are safety and reliability issues with the digis, but I don't have any personal experience with them, so that's all secondhand anecdotal evidence. Apparently they're not UL listed either. Magnetics have always been fine for me.

Don't worry if you're overwhelmed. There's a lot of info ...

Not meaning to hijack this thread but a few more questions.

ceestyle said:

That said, I'm pretty sure that if you get an HPS ballast, you are better off with a CMH for veg than with a MH conversion bulb.

The Blue runs on a MH ballast, whereas the CMH runs on a HPS ballast. Unless you're going to get two ballasts straight away - which from your other thread I gather you are not - you are going to get an HPS ballast. Then just decide whether you have the cash for a CMH instead of a MH conversion.

Click to expand...

So a straight MH definitely needs it's own ballast and dedicated socket and a dual MH/HPS lamp would need both kinds of ballasts. I was under the impression I would only need two ballasts if I wanted to run them both at the same time but I see now each requires its own gear.

1)But does a conversion MH screw into an HPS socket and run on an HPS ballast?

The "conversion" part means it's been converted somehow to work with HPS socket and ballast I guess. The problem with the Hortilux MH conversion then is it's spectrum is not much different than the Hortilux Super HPS. The advantage of the Hortilux Blue was that beautiful full, balanced spectrum but I see it requires its own equipment to run. I was looking at dual digital ballast thinking it would rus 400w bulb produces about the same spectrum energy and lumens as the Hortilux 400w blue so would at least be great for vegging. If I just vegged with and used the HPS ballast it would be a lot less complicated. Would be real nice if a 600w HPS ballast would run a 400w CMH or MH though. I think 30,000 lumens would be more than enough to veg and keep the plants bushy and compact.

Don't worry if you're overwhelmed.

Click to expand...

Funny, this thread popped up just when I thought I had a handle on it.

What is a cool tube? I looked it up and couldn't find a specific brand but a bunch of "build your own cool tube threads and videos. Is it a generic name for any type bulb that's fitted inside a tube and cooled by airflow or something?

Thanks again.

VirginHarvester said:

Not meaning to hijack this thread but a few more questions.

So a straight MH definitely needs it's own ballast and dedicated socket and a dual MH/HPS lamp would need both kinds of ballasts. I was under the impression I would only need two ballasts if I wanted to run them both at the same time but I see now each requires its own gear.

1)But does a conversion MH screw into an HPS socket and run on an HPS ballast?

Click to expand...

Yes.

The "conversion" part means it's been converted somehow to work with HPS socket and ballast I guess. The problem with the Hortilux MH conversion then is it's spectrum is not much different than the Hortilux Super HPS. The advantage of the Hortilux Blue was that beautiful full, balanced spectrum but I see it requires its own equipment to run. I was looking at dual digital ballast thinking it would run both and it will not. But, the 400w CMH has a similar spectrum and lumen output to the 400w Hortilux MH blue and uses same ballast and light fixture as an HPS.

Click to expand...

The MH conversion has much more blue than the HPS, and is much weaker in the yellows and reds. Compare the Metal Ace to the Super HPS here.

2) Would a 600w HPS ballast run a 400w MH conversion and/or the Phillips 400w CMH? If not, it seems to limit me to a 400W Super HPS or buy an extra ballast to use both since the CMH is only available up to 400w.
at's fitted inside a tube and cooled by airflow or something?

Thanks again.

Click to expand...

No, the ballasts are specific for the wattage bulb.

A cooltube is this: You can just attach ducting to it with your inline fan. It is a great way to control heat. I've got a 400W that works awesome. It functions like any other air-cooled fixture, but takes up very little space, and if you remove the reflector from the inside, it's ideal for a vertical grow setup.

What size is your grow area going to be?