Cmh bulb Vs hps

xtsho

Well-Known Member
There have been threads regarding these bulbs. It looks like you can now use them with digital ballasts. They used to only work with magnetic ballasts. I thought CMH bulbs operated at a low frequency square wave. I wonder how they would work with most digital ballasts that operate at high frequency. I know next to nothing about the dynamics of the technology. But I have picked up a little.


 

Frogglet Legs

Well-Known Member
Thanks man yeah I did search at previous posts but nothing really answered my question if the difference would be worthwhile....might jus up my cooling to handle a 1000 hps instead
 

OldMedUser

Well-Known Member
I'm using a 400w Philips CMH on a mag hps ballast now. Nice light and as I have 3 600w digitals I wouldn't mind getting a couple of those bulbs myself.

Don't really need them but like shiny new things. :)

:peace:
 

PJ Diaz

Well-Known Member
Personally I don't think it's worth switching to cmh from hps unless you are using the low frequency square wave technology, which these do not appear to utilize. I ran a 400w cmh on a mag ballast for a bit, then switched to a 315w cmh square wave digi ballast, and the 315w kicked out around 10% more light than the 400w chm mag ballast.
 

Frogglet Legs

Well-Known Member
Good to know the bulbs arnt cheap. I will stay with my hps for now and upgrade in the near future. Thanks for replys
 

xtsho

Well-Known Member
Thanks man yeah I did search at previous posts but nothing really answered my question if the difference would be worthwhile....might jus up my cooling to handle a 1000 hps instead
I saw the Digital and Magnetic compatible and was thinking it might be worth getting one. But the more I looked into it the more it seemed that they are not going to perform like a normal CMH bulb and ballast designed for them.
 

OldMedUser

Well-Known Member
I saw the Digital and Magnetic compatible and was thinking it might be worth getting one. But the more I looked into it the more it seemed that they are not going to perform like a normal CMH bulb and ballast designed for them.
A while back I was checking out the Hortilux 600w CMH. They sell a special digital ballast with it and neither are cheap but after examining the PPFD specs they really aren't worth the money IMHO.

:peace:
 

rkymtnman

Well-Known Member
Personally I don't think it's worth switching to cmh from hps unless you are using the low frequency square wave technology, which these do not appear to utilize. I ran a 400w cmh on a mag ballast for a bit, then switched to a 315w cmh square wave digi ballast, and the 315w kicked out around 10% more light than the 400w chm mag ballast.
agreed. i'd buy 2 of the real deal LFSW ballasts and the 315w philps agro bulb. run it vertically like it was designed.
 

OldMedUser

Well-Known Member
I only use the cmh during the colder months to supplement my LEDs for a bit of IR heat. The rest of the year LED alone kills.
My grow room is cool enough I need my HIDs even in the summer or I'm using a heater to keep the temps up to 75F even when the lights are on and any savings from LED would go to that. Just running the 400w CMH in there now and it doesn't get warm enough to make the exhaust fan kick in but will be switching to a 600w hps soon and that should be enough to get it going being summer now.

The room is basically in a concrete bunker under the house with two walls and the floor in contact with the cold clay ground we have here. Zap them with the IR thermometer and they are never warmer than 60F so built-in passive A/C. :) If I try to raise my VPD to normal those cold surfaces get sweaty with condensation but we have really low RH here so unless I add a lot of moisture to the air no problem other than living with low RH.

:peace:
 

Lucky Luke

Well-Known Member
As far as i'm aware you need a square wave ballast to unlock the potential and advantages of CMH over HPS.
 

xtsho

Well-Known Member
A while back I was checking out the Hortilux 600w CMH. They sell a special digital ballast with it and neither are cheap but after examining the PPFD specs they really aren't worth the money IMHO.

:peace:
I really think that these bulbs are not worth bothering with. They appear to be just an expensive bulb that isn't going to deliver any better than the existing HPS they would replace.
 

PJ Diaz

Well-Known Member
what K leds? and what K cmh do you run? i woulda guessed the combo would beat solo leds
I'm using different LEDs right now, and not using the cmh because it's the warm season, but it was 3100k cmh with LEDs that used 4k white plus 630nm and 660nm red diodes. The thing is the cmh is simply less efficient that LEDs so less photons for the wattage.
 

MICHI-CAN

Well-Known Member
I gave the heat and bulb costs up long ago. But a 600MH in veg and 1000W HPS in flower will produce very well in proper space.
 
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