Philips 315w CDM Elite (CMH)

[Beta Test Team]

My two cents about watts per square foot:

I think we all should deprecate the use of watts per square foot, because plants don't use watts, they use photons. While using watts/f2 is okay as a bare minium, because practically no one is actually measuring irradiance, it shouldn't be held up as the ideal method to calculate the correct lamp(s) for a given space.

Not only is watt/f2 flawed because it's only about input power, which plants don't use, but it's also flawed because it doesn't speak to distance from canopy (as distance affects radiation intensity at canopy), it doesn't speak to the amount of PAR range radiation emitted per input watt (as the lamp emits considerable energy above 700 nm), and it doesn't speak to irradiance uniformity over the canopy.

Better would be people start actually measuring irradiance, at least with a good lux meter (at about $200) and converting lux to PPF (https://www.icmag.com/ic/showthread.php?t=303009), or using an Apogee quantum sensor (at about $400), but better than both would be using LI-COR quantum sensor (at about $1,000).

To me this would be like a grower simply guessing at pH of the nutrient solution by the amount of pH down or pH up added, rather than actually measuring the pH with a pH meter.

I think it's high time growers start actually measuring the irradiance at canopy, rather than using the very old method of watt/f2.

 

[m8s4]

It seems from you response maybe you want to use Greenpower in flowering due to the greater red in the Greenpower? If so, I think you're basing your plan on flawed logic, that is, the often made claim that HPS (red) is for flowering and MH (blue) is for veg.

Yeah this is my thinking atm, Im in progress of my first grow so my knowledge is based on what is written on the cannabis forums where most of the people claims that the blue spectrum is more usable during the veg stage and red one during the flo but in spite of that I have been using hps from the beginning of my grow ... just thought a light with more of blue spectrum (and uv-b or something) will be better idea (if would have both of them and could use only one at a time)

Thanks for your links ... will try to understand it

 

[Jhhnn]

It seems from you response maybe you want to use Greenpower in flowering due to the greater red in the Greenpower? If so, I think you're basing your plan on flawed logic, that is, the often made claim that HPS (red) is for flowering and MH (blue) is for veg. But that claim isn't correct, it's based off of very strong misunderstanding and assumptions of 'experts' from over 20+ years ago.

Check out this thread to see how Cannabis absorbs spectrum from veg to flowering (there is very little change):
https://www.icmag.com/ic/showthread.php?t=293045

And this thread about how radiation is used for various plant responses:
https://www.icmag.com/ic/showthread.php?p=6718314

In other words, you can use the Greenpower for all growth stages (veg to flowering), or the 942 for all growth stages, and have great results. There's basically zero valid reason to use 942 for veg/pre-flowering and Greenpower for flowering, however.

Everybody deals with the HPS vs MH controversy in their own way. A lot of strong opinions are formed one way or the other because of the radically different spectrums, not necessarily because of different results. It's like religion- people become believers in different methods. The truth doesn't matter. I solved that controversy in my own way by using a dual arc lamp to get the best of both worlds.

I think that part of what's happened is that myths have shaped marketing of the 315w lamps. They're all closer to sunlight than virtually anything else. The actual differences in spectral output between them is really quite small in comparison to the differences between HPS & MH. Big commercial ops might gain a little using the agros, but the rest of us will likely play hell trying to ascertain the difference between any of them.

 

[Beta Test Team]

Everybody deals with the HPS vs MH controversy in their own way. A lot of strong opinions are formed one way or the other because of the radically different spectrums, not necessarily because of different results. It's like religion- people become believers in different methods. The truth doesn't matter. I solved that controversy in my own way by using a dual arc lamp to get the best of both worlds.

I think that part of what's happened is that myths have shaped marketing of the 315w lamps. They're all closer to sunlight than virtually anything else. The actual differences in spectral output between them is really quite small in comparison to the differences between HPS & MH. Big commercial ops might gain a little using the agros, but the rest of us will likely play hell trying to ascertain the difference between any of them.

The thing about MH vs. HPS is it's not based on facts, only conjuncture and incomplete understandings and incomplete data sets. With growers doing "tests" without accounting for important factors that affect the outcome, mostly notably not actually measuring PPF. Which is something I personally abhor. So that's why I always try to post provable facts, and try to base all decisions and opinions on provable facts.

For too long this industry and hobby has been based on assumptions and conjecture, which go counter to facts. But I know I'm in the minority, as you're very correct that many growers treat this topic as religion rather than science.

I do totally agree that the differences between the Greenpower and the 942 aren't great in the PAR range. And either one will grow great plants. However, for the Agro (Greenpower), if the PPF is the same for the Agro and the 942, the Agro won't likely give better yields, the opposite is likely true based upon analyzing the spectra of both lamps. Here is something I wrote someone last night:

The main difference between the Greenpower and the 942 is the Greenpower has more red range (with a large spike at about 675-700 nm) relative to total PAR range (400-700 nm) vs. the 942. So the main difference between the Greenpower vs.the 942 is the Greenpower's efficiency in turning watts into PAR rage photons, where the Greenpower is more efficient, so less electricity is needed to provide the same PPF from the Greenpower vs. the 942. The Greenpower has about 1.9 umol/s in PAR range per input watt, while the 942 has about 1.7 umol/s in PAR range. This topic is where the 10% greater PAR range output (umol/s) comes from you cited, this is about efficiency, not effect on plant growth.

And that 10% value isn't as important as it sounds, in the broad sense, because you wouldn't need more 942 than Greenpower to reach the same PPF, because we're not working in absolute values. That is, goal irradiance is range of around 200 to 300 PPF, that is, from around >600 to <1,000 PPF is an ideal goal.

However, and this is VERY important, the effect on rate of photosynthesis (i.e. weighted PAR range irradiance, known as "YPF") from the GreenPower and 942 is VERY small. So even though the Greenpower has more red that doesn't necessarily translate into more photosynthesis per PPF, if the PPF is the same for both lamps. The Greenpower has a YPF to PPF ratio of 0.898, while the 942 has a YPF to PPF ratio of 0.892. What that means is for every 100 PPF from the Greenpower there's 89.8 YPF, and for every 100 PPF from the 942 there's 89.2 YPF. And using YPF is the best way to measure irradiance effect on photosynthesis. So the Greenpower has about 0.7% greater YPF output than the 942.

That 0.7% greater YPF from the Greenpower than the 942 is more important to consider than the 10% greater PPF from the Greenpower than the 942.

GreenPower pros vs. the 942:
- Greater efficiency in turning watts into photons within PAR range, so you use less electricity to provide the same PPF vs. the 942.
- Very slightly greater YPF/PPF ratio, so slight it doesn't really matter. This is about the effect of the lamps on rate of photosynthesis.

942 pros vs. the Greenpower:
- Better spectrum for plant growth in PAR range in terms of many photobiological reactions from light, such as light tracking by leaves and stomatal opening, with very similar effect on rate of photosynthesis as the Greenpower.
- Less heat generated in terms of NIR radiation (>700 nm)
- Better UV-B and UV-A output, by a wide margin.
- Better blue:red ratio.

 

[HorseBadoritiz]

After seeing how well the mogul base 315 worked, I just got 2 more kits from Advanced, and they came within a week of ordering. 200 willies each.

They DO NOT come with sockets, but do work in a standard mogul based one.

I'm running them in 3 different reflectors and chambers: an old Super Sun with a smooth interior (vs hammered) and side venting (as opposed to the newer end vented), a Sun System Maximum yield, and an OG... it's what I've got, LOL!

I've only grow with 400W CMH's, bare vertical at first, then OG vertical, and hooded horizontal. Reflectors have given me the best results, but that may be due to the learning curve that applies to how to grow indoors!

I have a pos light meter, and I'm more interested in results rather than numbers... and I am stoked seeing that less is more!

Anyway, the 4100K did me well with the CMH's, and it looks like it's doing just fine with these 315's.

I'm a bit blazed from from Retro CMH grown Sunshine Daydream, and have 3 more under the 315 in the OG... so I hope I can come back with an actual comparison... 'ere!

 

[theLumberjack]

I think that wearing sunglasses when working in a room that has these makes sense.....

 

[Jhhnn]

I think that wearing sunglasses when working in a room that has these makes sense.....

When testing, I quickly discovered that just glancing at the emitter left a white spot in my vision for some while. Don't do that. The intensity is amazing.

Maybe I'll get one of those green visors like Hunter S Thompson wore...

 

[theLumberjack]

I might have to return my visor. I think the real problem was cleaning chemicals.... specifically h202. fml

 

[m8s4]

One more question guys ...

How does it look with the heat ? Does the 315w bulb produce as much heat as let say HPS 250w/400w/600w ? I will go for one reflector with two bulbs and just wondering should I pick Dimlux with an air extracting option or should I take D-papillon one without it (which I would prefer personally). I found a growlog where Lec 315w system had been used and that guy said it produces similar level of heat as his 400w LED panel and the heat can be managed easily. How it is in real ?

Thanks

 

[Scrappy-doo]

3 x 315's is way easier to cool than my 1k hortilux was.

 

[rives]

One more question guys ...

How does it look with the heat ? Does the 315w bulb produce as much heat as let say HPS 250w/400w/600w ? I will go for one reflector with two bulbs and just wondering should I pick Dimlux with an air extracting option or should I take D-papillon one without it (which I would prefer personally). I found a growlog where Lec 315w system had been used and that guy said it produces similar level of heat as his 400w LED panel and the heat can be managed easily. How it is in real ?

Thanks

I think that it depends on what you are used to and what your setup is.

The 315 will certainly be much cooler than either a 400 or 600w HPS, and very possibly cooler than a 250. In my first application, I used the same extraction fan that I had been using with either a 325 or 440 watt LED, but instead of just exchanging the tent air, I stuck the inlet up high and then ducted it through an air-cooled hood. The result was that the temperatures were roughly 5-8 degrees cooler than with the LEDs. With the ventilated hood, the plants can touch the glass without burning, and the hood itself is barely warm to the touch.

Without the enclosed hood, the temperatures at the leaf level are obviously going to be higher at any given distance than if the hood is ventilated. However, if you were running any other HID open before, the 315 is going to be substantially cooler. It will be warmer than an LED at the leaf because the majority of the heat from LEDs goes out the back. Overall tent temperature will probably be similar to a roughly comparable LED.

 

[m8s4]

As always a proper answer, thanks. I have been running HPS 250w at the beginning and then HPS 600w. What I can say - not air cooled HPS 250w was making very similar temperature in my tent what air cooled reflector with HPS 600w, oscillating between 79-82F but I'm running a day (light) for my plants during a night time to lower the temp as much as possible.

And the summer time is coming ...

Don't know how to organize it tbh :/

 

[theLumberjack]

my surface temps under my 315 at 12" are the same as 20" under my air cooled 600watt hps. my lumens are doubled.

 

[Jhhnn]

One more question guys ...

How does it look with the heat ? Does the 315w bulb produce as much heat as let say HPS 250w/400w/600w ? I will go for one reflector with two bulbs and just wondering should I pick Dimlux with an air extracting option or should I take D-papillon one without it (which I would prefer personally). I found a growlog where Lec 315w system had been used and that guy said it produces similar level of heat as his 400w LED panel and the heat can be managed easily. How it is in real ?

Thanks

One of the things people don't understand very well is that all the electrical current dissipated by a HID or LED system turns into heat, one way or another. There's convective heat from ballast inefficiency & high temp lamp operation along with the radiant heat from the lamp as photons of any wavelength. That radiant heat becomes convective/ conductive heat when absorbed by any surface. Only a small fraction of that energy is used to create chemical bonds in plant matter, stored heat.

Watts are heat for our purposes. OTOH, not all radiant watts are visible light.

A key element in CDM performance is shifting of infrared output into the visible range where plants can use it.

http://www.cycloptics.com/sites/default/files/USU_spectral_analysis.pdf

Increased ballast efficiency also plays a role.

Higher pressure operation than standard MH also broadens the emission bands of the different elements within, thus flattening the peaks & valleys of the spectral graph. That seems to be useful to plants, as well.

So if you can get the same or better performance from 315w as from 400w you'll have correspondingly less heat/power to deal with. OTOH, if you replace a 600w system with two 315w systems, you'll have considerably more light with about the same amount of heat & power consumption.

I'm hoping that two 315 systems will do almost as well as my current 1000w but I really have to wait a few months to find out because it involves teardown & modifications to current equipment. I'll save ~450w/hr of operation, cutting the heat and the electric bill.

 

[Beta Test Team]

my surface temps under my 315 at 12" are the same as 20" under my air cooled 600watt hps. my lumens are doubled.

Just out of curiosity, how you are measuring temp? Using IR thermometer or traditional thermometer? And in direct radiation (leaf temp) or indirect radiation (air temp)?

And just to point out, comparing HPS to CMH using lumen radiance or lux irradiance is very error prone. This is because lux (i.e. lumen per square meter) and lumen give more 'weight' to green range, and CMH has much more green range output than HPS. So even if CMH lumens are doubled that doesn't mean 100% more PAR range radiation from CMH vs. HPS. To compare disparate spectra (e.g. CMH spectrum and HPS spectrum) it's best to use unweighted measurement of quanta, which would be PPF (the same thing has PPFD), with a good quantum senor (i.e. flat quantum response, such as LI-COR) or good lux meter converting lux to PPF manually.

 

[theLumberjack]

thanks, i was afraid of that being the truth.... but i still like my 315's a lot.

i use IR gun on leaf surface. errors??

 

[HUGE]

Use fingers on leaf surface. Grasp leaf between the sides of 2 fingers. The sensitive part. If it feels cool your heat is ok. If not feeling COOL between fingers. Shit is too hot.

 

[Beta Test Team]

thanks, i was afraid of that being the truth.... but i still like my 315's a lot.

i use IR gun on leaf surface. errors??

Oh, I totally agree they cause less heat than HPS. Just wondering how you measured.

Using IR thermometer on the leaf surface isn't an error, but it also doesn't tell the air temp. Testing leaf temp is very good thing to know, because you don't want left temp to exceed air temp by very much during the day (not more than about 5-8'F) and you don't want leaf temp to be much cooler than air temp at night (within a few degrees). And measuring leaf temp is the most accurate way to calculate vapor pressure deficit (which is the most accurate way to define humidity effects on plant growth).

But measuring leaf temp isn't the same thing as air temp. To measure air temp with an IR thermometer, an accurate and easy way to do so would be using two pieces of white paper, where one piece of paper is above the other by a few inches, to shade the lower piece of paper, and you aim the IR thermometer at the lower piece of paper.

If you were to measure air temp with a traditional thermometer you would cover it with something, like paper or something else to block direct radiation (like a vented box), and take readings.

When measuring air temp the goal is to not allow direct radiation to affect the temp readings, that is why they're taken out of direct radiation.

Optimally you'd measure air temp at the canopy, away from walls, in shade, with air movement while measuring.

This document you may like:
Measuring Greenhouse Temperature
http://www.flor.hrt.msu.edu/assets/Uploads/Measuringtemperature.pdf

 

[theLumberjack]

i will try that paper method and see how much it varies from my thermostats reading.

 

[flat9]

What's the consensus on 942 vs 930 for the entire grow?