Thread open for discussion! Lets keep it civil and on topic.
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Rock On!
Rock On!
This thread has ALWAYS been about the Philips 250/400 watt CMH bulbs.
Am not trying to change anybody's mind....
...just want them to see the light....
Rock On!
This thread has ALWAYS been about the Philips 250/400 watt CMH bulbs.
Am not trying to change anybody's mind....
...just want them to see the light....
I'm thinking of adding a 3rd 400w to my grow. If I don't reconfigure anything, that will bump me up to 75w/sq. ft.
There's an old post by knna where he states that CMH will seriously outperform HPS at that density.
So my question is....
If you were going to have 3x400w and you already had 2 CMH lamps... would you add an HPS (and keep two CMH), or two HPS (and keep one CMH) or 3 CMH?
There's an old post by knna where he states that CMH will seriously outperform HPS at that density.
So my question is....
If you were going to have 3x400w and you already had 2 CMH lamps... would you add an HPS (and keep two CMH), or two HPS (and keep one CMH) or 3 CMH?
I veg with 1200 watts at 100 watts per square foot. I had two HPS and a CMH, I put retro white CMH's in the HPS fixtures and the plants grow greener with better leaf thickness. I would call it a plus.
No one single light has ever worked as well as a combo, but CMH is about as close as I have come.
No one single light has ever worked as well as a combo, but CMH is about as close as I have come.
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I'm just following along here since I don't have any direct experience with CMH, but I think that if you could arrange the lamps to where you could evenly cover the entire canopy with all three lamps (achieving a "blend"), then adding the HPS would be best. However, if each lamp lights just a segment of the canopy (which I think would be the case with your arrangement), then you would probably be better off with all CMH.
Thanks! What do you flower with and at what densities? (I'm just curious since you are vegging at 100w/sq.ft.)
(These clones just went in, so lights were raised and are being lowered over the next few days.)
I appreciate the quick replies, guys.
The whole table is 6'x2.5' and the bulbs are hung so that each lights "half" of the table. (And no, the disco ball does not live there full time. I put it in there when I take pictures as part of a running joke in my thread.)
So if there were an HPS in the center (or a CMH) it would be (at most) ~3ft from the furthest plant.
Three feet away for a 400 is getting to be a bit of a stretch, I think, but it still might work to round out the spectrum. It would be worth a try - the nice thing is that it would only be the cost of the lamp since the ballasts are the same. Actually, I think that Advanced Technology Solutions was giving away a free HPS lamp when you purchased a CMH lamp.
MostHigh
Member
I was an early adopter of CMH, of the 400 watt variety.
Since the lamp still does produce good results, I've kept it in play. However, I've never seen it give me anything that can be considered superior to HPS.
There are drawbacks. The main disadvantage is...heat, and lots of it. My 400CMH runs nearly as hot as my 600HPS. I have both in the same hood...when I run them together, I absolutely have to raise the hood, or the tops go into slow bake and the plants soak up water faster than they metabolize nutrient. When I run the hood with 400/600 HPS, I do not have to raise the hood. Also, with the CMH, I'm forced to use the hood's glass to help prevent at least some of the heat from radiating into the garden.
I can't flat out knock the CMH...however, and I'm speaking to my specific lamp (which as far as I know, suffers a quality control issue) and my specific grow environment...it simply does not perform as it was billed to.
The main, and as far as I can see, only advantage to CMH is...the cost. If one is on a tight budget, and doesn't have the coin for multiple lamps and ballasts...the CMH is the option to give the most consideration to.
Since the lamp still does produce good results, I've kept it in play. However, I've never seen it give me anything that can be considered superior to HPS.
There are drawbacks. The main disadvantage is...heat, and lots of it. My 400CMH runs nearly as hot as my 600HPS. I have both in the same hood...when I run them together, I absolutely have to raise the hood, or the tops go into slow bake and the plants soak up water faster than they metabolize nutrient. When I run the hood with 400/600 HPS, I do not have to raise the hood. Also, with the CMH, I'm forced to use the hood's glass to help prevent at least some of the heat from radiating into the garden.
I can't flat out knock the CMH...however, and I'm speaking to my specific lamp (which as far as I know, suffers a quality control issue) and my specific grow environment...it simply does not perform as it was billed to.
The main, and as far as I can see, only advantage to CMH is...the cost. If one is on a tight budget, and doesn't have the coin for multiple lamps and ballasts...the CMH is the option to give the most consideration to.
This thread is so crazy huge now.... wow.... Can someone help me figure out where to get a 5kv pulse rated socket? My socket on my DIY reflector is 4kv pulse rated. Will this be a problem? I checked 1000bulbs and several other sites and everything is 4kv rated 
I have no money, but I do have a gift card on Amazon, but I can't find a 5kv socket on there either. Are these specialty or something?
I have no money, but I do have a gift card on Amazon, but I can't find a 5kv socket on there either. Are these specialty or something?
I recently got my 400W CMH lamp(Philips Mastercolor Retro White). I have test-fired it, but I still don't know if I am asking for trouble using a 4kv socket. I really want to solve this issue as quickly as possible.
Here's a pic of my home-made S51 ballast using a PC case(cover not shown):
Here are a few shots of the CMH running:
So far I am very impressed with how it lights up the chamber. It's so much brighter in there than the HPS made it. Lumens be damned! This lamp is so much brighter I have to wear sunglasses in there or I get a headache. The HPS was nowhere near this intense. My HPS lamp was a Philips Ceramalux for reference. Here's a pic of the HPS running:
Here's a pic of my home-made S51 ballast using a PC case(cover not shown):
Here are a few shots of the CMH running:
So far I am very impressed with how it lights up the chamber. It's so much brighter in there than the HPS made it. Lumens be damned! This lamp is so much brighter I have to wear sunglasses in there or I get a headache. The HPS was nowhere near this intense. My HPS lamp was a Philips Ceramalux for reference. Here's a pic of the HPS running:
Here is a comparison shot:
Cabinet is up and running. 256W of T-8 side lights and a 400W Philips Master Color Retro White overhead. I have 10 of the 11 plants I have ready in there so far.
smokesalot420
Member
PLEASE wear glasses when near or working under these lamps, the UV light isn't good for your eyes (or skin)
I've been trying to. I'm actually going to dig out my torch welding goggles if I can find them, or buy some new ones. It may look dorky, but regular sunglasses don't fit over my glasses well.
Live to SEE another day
Illumination
Member
Apologies but CMH does NOT emit hardly any uv at greater than 12 inches distance and even at 1 inch the uv is not at harmful levels... per uvb meter
It's not monkeys designing these lamps. The arc tube itself is designed to emit a more blue-shifted spectrum, and the jacket is designed to refract that to the desired SPD. Creating more UV-B would be really easy, but these lamps are designed to be worked under, not for plants. It would be really great if someone would develop a horticultural version of the Retro White lamps.
Illumination
Member
That is from checking for uvb with a meter and a 400 watt CLEAR non coated bulb...I stand by this as is FACT on these bulbs...The 400 watt clear non coated bulb heralded to produce uvb and hence the better growth is BS...The meter does not lie friend..also these bulbs were not designed for horti purposes so they MUST block uv as they are to be used over humans
This leads to me to conclude that it is the better wider spectrum which produces the desired results...
I supplement the 2 cmh and vertical hps with 4 foot t5 arcadia 12% d3+ t5 ho uvb bulbs as well as actinic + and planta t5 as well as some Megaray ZOO bulbs on movers for the uv...the uvb effect is VERY pronounced in the c99's I just finished...
