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

[VirginHarvester]

What size is your grow area going to be?

4x4.

Thanks for the link. So with a cooltube you just attach ducting to each end and run air through it? The reflector looks really small. Is it big enough and direct enough to straight down to the canopy?

Thanks again.

 

[ceestyle]

4x4.

Thanks for the link. So with a cooltube you just attach ducting to each end and run air through it? The reflector looks really small. Is it big enough and direct enough to straight down to the canopy?

Thanks again.

Yeah; it's pretty money.

If you only have one light, tubing only needs to attach to one end and pull air from the grow area.

4x4 is a perfect size for a vertical grow with a cool tube. Hang a 600 in the center vertically with no refector and run the ducting straight up. I f you've got the vertical room, throw in a shelf of two. Do a search for vertical grow and do some browsing.

 

[object16]

Hi, the way to tell how many plant lumens you lamp is giving you, is to read the literature on the internet: This article shows the difference between HUMAN EYE lumens, and PLANT lumens, two totally and completely different things. Notice how blue light is important source of plant lumens, but the added "weight" that yellow and red light in PLANT LUMENS, means that if you look at a CMH lamp spectrum, and compare to a 4000K Metal Halide spectrum, that the CMH has a lot more of the extremely effective yellow and red. That is why I consider CMH to be perfect for vegetative growth, and early flowering phase of the first 10 - 14 days. After that, the "heavy weight" HPS loaded with yellow and red lumens that count very high when calculating PLANT LUMENS, is the best to put on heavy buds.

Towards a Plant Growth Lumen

Almost all consumer lamps are now labelled with watts consumption and lumens output. For humans, lumens per watt is a good measure of the efficiency of a lamp in meeting human ability to see, because it is based on the relative sensitivity of our eyes (the red curve at right). Plants respond very differently to light than humans do. The green curve shows the relative effectiveness of light in producing plant growth. The black curve shows a common definition of plant growth effectiveness used by the lighting industry - it matches the needs of plants only a little better than lumens do (cf. Bugbee)
Plants respond to wavelengths other than the green curve for non-growth functions such as flowering initiation, just as humans respond to wavelengths other than the red curve for non-visual needs, such as the production of Vitamin D. However, fresh-water aquarists mostly aim for plant growth.
What we aquatic plant growers need is a true plant-growth lumen (PGL). Here is how to calculate one.
First, obtain the spectrum of the lamp output (you'll have to get it from lighting engineers at the manufacturer; you won't find it on the package or in stores), and its lumen rating. If the spectrum is supplied in energy units such as watts (most are), you must convert it to a photon scale by multiplying each intensity by its wavelength.
Then, using the table below, multiply each spectral value of the lamp by the matching spectral factor for plants. For example, multiply the lamp intensity at 450 nm by 0.213 The result will be the spectrum of the lamp as a plant sees it. Add up all the numbers and call the result P (for Plant).
Next, multiply the lamp spectrum by the matching spectral factors for lumens. The result will be the spectrum of the lamp as a human sees it. Again, add up all the numbers, call it L (for Lumens).
Finally, multiply the lamp lumens by P and divide by L to get the PGL.
Here is an example: a 60 W incandescent lamp, whose output is shown in the black curve of graph 2 at right. The lamp output is 855 lm. Following the above procedure, the red curve is the way a human sees the light, the green, the way a plant sees it. The ratio of P to L is 1.26, so it produces 855 x 1.26 = 1077 PGL.
If the spectral data is not in 10 nm bands, or covers less range than 350-750 nm, this method will still work as long as the data is uniformly spaced over its range. Simply use the nearest values in the table below, the same ones for both P and L. Since the method only calculates a ratio between human and plant lumens, the units of lamp spectral intensity don't matter, as long as they are in photons, not energy.
The result of such analyses is clear: very few 'plant growth' or 'aquarium' lamps outperform cheap standard-spectrum fluorescent tubes or compact fluorescent lamps for growing aquarium plants.
Graph 3 at right shows why. Three lamps are shown, with their output in relative photons per second in 10 nm bands. The black curve is a standard warm-white tube, the others two different plant-growth lamps. The extended spectrum of most plant-growth lamps is obtained at the expense of total output. And, the tiny production volume of the specialist lamps compared to standard warm-white makes them much more expensive.

human, plant and 'quantum' sensitivity

incandescent lamp performance

plant-growth vs. warm-white
typemodelwattsinitial lumensPGLPGL/watt straight filament incandescent15T101512017211 coiled filament incandescent60A1960855107718 halogen incandescentPAR601050128021 warm-white fluorescent18"1583447832 warm-white fluorescent24"20125371836 cool-white fluorescent24"20120075038 warm-white fluorescent36"302123121641 2700 K compact fluorescent
20120084142 warm-white fluorescent48"403117178545 Hagen fluorescentAquaGlo2040095047 Hagen fluorescentSunGlo20123098849 Hagen fluorescentPowerGlo201100104552 special purpose lamps aquarium fluorescent#12075070735 aquarium fluorescent#22095074037 aquarium fluorescent#32087569034 plant-grow fluorescent#42048074037 plant-grow fluorescent#52075056028 plant-grow fluorescent#62067064032 metal-halide discharge
503000189038 high-pressure sodium
352240153444
Now that you have a Plant Growth Lumen, how do you use it to grow aquarium plants?
A commonly quoted measure of aquarium lighting in North America is 'watts per gallon': tube-fluorescent watts per US gallon for 10 hours per day. 1 watt per gallon is considered low light, 2 medium, 3 high. Although easy to criticise on the surface, it has proven to be an acceptably reliable measure in practise. So, how can it be converted to units that can be understood by the majority of the world that has access neither to US gallons nor to US lamps?
The efficiency of fluorescent lamps varies with length, as shown above. Most aquarium lamps here are 24", so 1253 lm for 20 W, 63 lm/W is a reasonable efficiency to use as a baseline for conversion. For a warm-white lamp, this is equivalent to 36 PGL/W. Since there are 3.785 liters in a US gallon, 1 'watt per gallon' converts to about 100 PGL-hr/l. For example, a 10 watt compact fluorescent lamp (420 PGL) operated for 12 hours per day over a 50 litre tank gives 420*12/50 = 100 PGL-hr/l, low light.
Now, you are ready to choose your plants based on their light requirements. Here is a listing of the best aquarium plants with their light requirements. Of course, plants respond to factors other than light - pH, fertilisers, trace elements, temperature, just to name a few. But, this note should help you get their light requirements in order.
John Sankey
other notes on physics
Notes

All light intensities on this page are in photons per second (Einsteins), not watts, as the activity of chlorophyll depends on the number of photons absorbed, not their energy.

Graph 1: The red curve is the CIE definition of the lumen (1924). The green is the average for 26 species of herbaceous plants from Inada, Plant Cell Physiol. 17(2):355-365 (1976). McCree has published similar results in Agric. Meteorol. 9:191-216 (1972), as have Sager et al. Trans. ASAE 31(6):1882-1889 (198. Black shows the most common definition of Photosynthetically Active Radiation (PAR) approximated by "quantum light meters". PAR is also known as PPF, Photosynthetic Photon Flux. All are normalised for equal areas under the curves.

Graph 2: The black curve was calculated from the Planck radiation equation for 2856 K (CIE Standard Illuminant A). The lumens output for a typical 60 W lamp is from the US FTC Facts for Consumers. Note that economy 60 Wbulbs, such as those sold by Rona, produce only 520 lumens.

The filament temperatures of the 15T10 (2470 K) and halogen (3000 K) lamps were calculated from their published lumens output and the Stefan-Boltzmann equation. The outputs of warm white lamps are averages from a survey by Joseph Sellinger. All other data was obtained from manufacturers' web sites, and refers to specific lamps. Brands are shown only when they perform significantly better than standard fluorescent lamps. Most manufacturers list only "initial lumens", so the above tables are based on them. (Fluorescent lamps typically produce only 87% of their initial lumens averaged over their lifetime.)

The table of spectral factors below shows the values of graph 1.
Spectral Factors

nm lumen plant
350 .000 .041
360 .000 .047
370 .000 .056
380 .000 .071
390 .000 .098
400 .000 .134
410 .001 .165
420 .004 .198
430 .011 .222
440 .023 .232
450 .038 .212
460 .060 .198
470 .091 .201
480 .139 .212
490 .210 .224
500 .326 .237
510 .504 .241
520 .706 .242
530 .859 .248
540 .951 .263
550 .993 .289
560 .993 .313
570 .950 .340
580 .868 .369
590 .756 .397
600 .630 .420
610 .503 .443
620 .380 .461
630 .266 .476
640 .175 .493
650 .108 .509
660 .061 .523
670 .032 .535
680 .017 .525
690 .008 .421
700 .004 .273
710 .002 .122
720 .001 .081
730 .000 .062
740 .000 .046
750 .000 .032
Towards a Plant Growth Lumen

 

[ceestyle]

Dude, you already posted this. This is not data showing anything about the CMH compared to MH. This is a crappy approximation of the right way to make the conversion.

 

[object16]

The chart in the article didn't come out with my cut and paste:
warm white fluorescent, 48" 40 watts 45 pgl/watt
metal halide discharge 50 watts 3000 initial lumens 1890 PGL = 38 PGL/watt
HPS 35 watts 2240 initial lumens 1534 PGL = 44 PGL/watt

When you look at the PGL chart,

380-450 = violet is 0.165 PGL weight
450-495 = blue is 0.201 PGL weight
495-570 = green is 0.248 PGL weight
570-590 = yellow is 0.369 PGL weight
590-620 = orange is 0.443 PGL weight
620-750 = red is 0.523 PGL weight
See how green light is actually more efficient for photosynthesis, than blue light!!!
how orange light is more than double the efficiency for photosynthesis compared to blue, and how red light, of which CMH has good and plenty, is a monster for photosynthesis - red is over 2 and a half times more efficient for photosynthesis than blue light. Using these numbers, you can very quickly, by using a spectrum chart, make pretty accurate calculations how to compare the plant growing capabilities of the various lamps. Remember though, that blue light also functions in a plant to keep it short and squat, and that blue is necessary for the production of chlorophyll, so that is why if we start out vegetative with a regular HPS lamp, the plants will get lanky and stretched out and not have as much chlorophyll, compared to CMH which will be squat, dense bushy and very green and healthy, which is exactly what you want.

 

[object16]

seestyle, just look up the manufacturer's spectrum for CMH. Notice how it is just like the sun, almost straight across. A regular metal halide has a blue peak, a green peak, a yellow peak, an orange peak, and a very little red peak. It is obvious that CMH has a monsterously bigger output in the red part of the spectrum, compared to a puny output in a MH regular. Red light is 0.523 PGL weight, which is twice the PGL weight of green light, which is only 0.248 It should be immediately obvious if you've checked the spectral output that CMH is a killer of a lamp. The fact that it runs on a regular HPS ballast is a bonus - big time!!!

 

[ceestyle]

seestyle, just look up the manufacturer's spectrum for CMH. Notice how it is just like the sun, almost straight across. A regular metal halide has a blue peak, a green peak, a yellow peak, an orange peak, and a very little red peak. It is obvious that CMH has a monsterously bigger output in the red part of the spectrum, compared to a puny output in a MH regular. Red light is 0.523 PGL weight, which is twice the PGL weight of green light, which is only 0.248 It should be immediately obvious if you've checked the spectral output that CMH is a killer of a lamp. The fact that it runs on a regular HPS ballast is a bonus - big time!!!

Unless you do the calculations, you cannot conclude just by looking at the spectra that one is better than the other. Period.

The information you posted is valuable, but it has all been gone over before ad nauseum. Look at the spectra here. The background curve is the same as you've provided. We know what PAR is.

You've provided a (crude) way of calculating the radiation relevant for plants, but you haven't actually done the calculation. You can't just look at the spectra for the bulbs and say one is better than the other, as they are all normalized - they are not absolute. Notice how each spectrum has exactly one point where it reaches the top of the plot? That's artificially imposed on the data so that you can see detail. You can't judge total output by the area under the graph as you see it. You have to do the math. Period.

Unless you can do the math in your head, you're just hand-waving by talking about the spectrum. CMH is weaker in some areas of the spectrum than MH, and stronger in others. Again, I'm not saying CMH isn't comparable to MH; I'm just saying that I don't know until I see the data.

 

[HydroChron]

I am wondering which would be better. Should i get a eb that can power both MH and HPS so that for veg I can use the Mh. And for flower I can use the HPS. Or should i stick with the metalic coil HPS ballast that i already have an just get a CMH. Im leaning towards the EB just due to the fact that it will produce less heat then the coil ballast. Ive heard mixed reviews or the CMH and i can see that it is alot of marketing. but at the same time could be great. Thanks for your time

 

[ceestyle]

i'd probably go with the HPS ballast and save the cash. you can always put the ballast outside your grow area.

switchable ballasts are really only useful if you only have one grow chamber and one ballast. once you have separate veg and flower rooms, you can just buy a MH or CMH.

 

[HydroChron]

i'd probably go with the HPS ballast and save the cash. you can always put the ballast outside your grow area.

switchable ballasts are really only useful if you only have one grow chamber and one ballast. once you have separate veg and flower rooms, you can just buy a MH or CMH.

thats the situation exactly. your prob right though. i have heard mixed reveiws of the digital ballasts. that they dont power the MH as well as they do the hps.

 

[ceestyle]

thats the situation exactly. your prob right though. i have heard mixed reveiws of the digital ballasts. that they dont power the MH as well as they do the hps.

The way I look at the CMH is this: it is not going to be better than an HPS for budding (opinion, evidence is inconclusive). Therefore, in the best case you have a bulb that is best for veg. Unfortunately the largest size you can get is 400W. There may or may not be a heat advantage.

So if you:

1. Have one space that is the right size for a 400W and anothing more.

or

2. Have two spaces the right size for 400W - one for HPS and one for CMH.

Maybe CMH is right for you. As for me, I already have a 400W MH, so I'm not in that boat.

 

[HydroChron]

i leaning toward just keeping it simple and getting the lumatek digital ballast and switching MH to HPS for flower. cause i would love to have the mh for veg. I am getting alot of excess heat from my coil ballast and would love to see that thing go out with the times. thanks again man

 

[mdgcmd]

I like that I can spend half as much on a bulbs and ballasts and get nearly the same and maybe more yield from one ballast and one bulb. It may not be better than an HPS but the CMH beats the HPS in vegging hands down. I can get nearly the same yield as a HPS as I can with a CMH. I will admit that the HPS has a slightly higher yield and is also slightly higher heat.

I think it is stupid to have a debate about which is better because they are all good bulbs, and do the job very well. For me there is not enough difference to make it an issue. For me it was an easy decision... one bulb, one ballast, all grow long, and a slight amount of less heat (not much trust me).

 

[OnSolomonsGrave]

I use a mix of CMH MH during veg and during flowering i swap the MH for HPS, rock hard dense nugs. I can also attest for the heat issues, CMH is almost touchable at full burn.

 

[ceestyle]

I like that I can spend half as much on a bulbs and ballasts and get nearly the same and maybe more yield from one ballast and one bulb. It may not be better than an HPS but the CMH beats the HPS in vegging hands down. I can get nearly the same yield as a HPS as I can with a CMH. I will admit that the HPS has a slightly higher yield and is also slightly higher heat.

I think it is stupid to have a debate about which is better because they are all good bulbs, and do the job very well. For me there is not enough difference to make it an issue. For me it was an easy decision... one bulb, one ballast, all grow long, and a slight amount of less heat (not much trust me).

Was it really a rice savings? How much was your CMH?

Do you two have thermometers? Is there any way you can place the thermometer in a few places, let the bulbs warm up, and compare them? MH, CMH, and HPS if you have them?

 

[ThatOneDude]

4x4.

Thanks for the link. So with a cooltube you just attach ducting to each end and run air through it? The reflector looks really small. Is it big enough and direct enough to straight down to the canopy?

Thanks again.

If you use a cool tube you loose the UVB output from the bulb. With proper ventilation, you shouln't need an air cooled hood. I can be in a space less then 8 cubic feet with a bare bulb and I keep temps in the cab in the mid 80's.

A cool tube also won't give you a very focused footprint. People use 'em, some love 'em, to each his own I guess. Just my opinion, other will have different ones.

 

[ceestyle]

If you use a cool tube you loose the UVB output from the bulb. With proper ventilation, you shouln't need an air cooled hood. I can be in a space less then 8 cubic feet with a bare bulb and I keep temps in the cab in the mid 80's.

Hmmm. I find it helps my heat issues lot, plus gives ventilation.

Can you explain why you lose te UVB radiation? I don't quite understand tha.

A cool tube also won't give you a very focused footprint.

Really? I did some work on reflector design, and I find that the reflector is actually too focused.

 

[ThatOneDude]

The way I look at the CMH is this: it is not going to be better than an HPS for budding (opinion, evidence is inconclusive). Therefore, in the best case you have a bulb that is best for veg. Unfortunately the largest size you can get is 400W. There may or may not be a heat advantage.

So if you:

1. Have one space that is the right size for a 400W and anothing more.

or

2. Have two spaces the right size for 400W - one for HPS and one for CMH.

Maybe CMH is right for you. As for me, I already have a 400W MH, so I'm not in that boat.

There is a BIG difference in heat and the way the bulb throws it. In my cab, I can stay steady in the mid 80's, with everything exactly the same, jand switching to the HPS bulb and temps shoot up to mid 90's in the first 1/2 hour. 80's are an acceptable temp for growing, 90's without CO2 are not......yes, the heat differance is a very big advantage to this bulb. Shoot up whatever arguments you want but, at 5-6 inches from the canopy with a bare bulb inside of a cab.

I dropped the challange eariler in this thread, show me someone with an exposed 400 watt HPS bulb 5-6 inches off of the canopy growing in a cab, until then, I wouldn't shoot off to much about the heat of the bulb, it's an advantage to every cabinet grower or anyone battling summer temps and there are a lot of us out there!

As for the mentions about the cost of the bulb, I tried to look at a few setups from people mentioning it...... I guess the one thing I want to throw out there is, what about the additional cost of the air cooled hood they are running? Don't compare just the price of the bulb, compare the cost of the set up. I think my air cooled hood was about $100 more then my umbrella reflector. Just something to give some thought too.

 

[ThatOneDude]

UVB can't penetrate glass, therefore it's lost....
I've seen both independant opinions as well as real tests on footprint and focused light from different reflectors, I've never seen a Cool Tube come out on top or close to it. I understand that there are set ups that people build that they may need one because of size, ventilation, ease of use, lack of engineering ability, or something, but, I've never seen any commericial growers using them in a large set up. I'm just guessing, I don't grow at that level, but, Im pretty sure it's because a large hood has always been shown to be better. Cool Tubes are cheaper then large reflectors, so why don't the pro's use them? I know the reasons I've read but, I'm certainly open to hearing how they maybe wrong.

For those of you that don't remember, I'm the one that started this thread. I've been through veg and flower with a 400 watt CMH bulb. I don't flower under the CMH anymore, for no other reason than I have a flowering room running 1000 watt bulbs. I do still use it for veging in the cabinet. MH doesn't compare for vegging, I saw it for myself. As for flowering, I can't give a true opinion, I have not flowered under 400 watts HPS at any point to be able to compare the differance.

 

[ceestyle]

There is a BIG difference in heat and the way the bulb throws it. In my cab, I can stay steady in the mid 80's, with everything exactly the same, jand switching to the HPS bulb and temps shoot up to mid 90's in the first 1/2 hour. 80's are an acceptable temp for growing, 90's without CO2 are not......yes, the heat differance is a very big advantage to this bulb. Shoot up whatever arguments you want but, at 5-6 inches from the canopy with a bare bulb inside of a cab.

I dropped the challange eariler in this thread, show me someone with an exposed 400 watt HPS bulb 5-6 inches off of the canopy growing in a cab, until then, I wouldn't shoot off to much about the heat of the bulb, it's an advantage to every cabinet grower or anyone battling summer temps and there are a lot of us out there!

As for the mentions about the cost of the bulb, I tried to look at a few setups from people mentioning it...... I guess the one thing I want to throw out there is, what about the additional cost of the air cooled hood they are running? Don't compare just the price of the bulb, compare the cost of the set up. I think my air cooled hood was about $100 more then my umbrella reflector. Just something to give some thought too.

I don't have any reason to disbelieve the heat argument, I just didn't see any data to show it. That's why I'm trying to get people to compare their HPS, MH, and CMH bulbs at certain distances from the bulb. If it is that much cooler, it is absolutely a benefit for cab growers. You can't argue that.

The cooltube is somewhat more expensive, but I don't have to add as much other circulation ventilation, as the blower does that for me. The can-fan and ducting I got were dirt cheap - thrown in with my light - so i'm unsure they cost new. I don't think they're expensive at all at HD, but again I don't know. Maybe 30-40 bucks

Still don't undersand the UVB thing.

So do you have a MH to compare the CMH with in terms of heat? I imagine that a lot of the heat from the HPS comes from the fact that it is so heavy in the red/IR.