Anyone have an Apogee AGP-MQ-500 quantum meter?

[fanleaf]

Well the mq-500 is in as of today. Now to wait till lights on time to play. I did take a few readings outside and playing with a few household cfl's lol.

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[fanleaf]

So heres some numbers!!! I have no idea what ppfd is ideal but I made a bunch of measurements and here they are. Maybe some of you that know what are good enough values can tell me how I'm lookin here.

Let me also say that I think my readings would have been a bit higher but with plants in there it was kind of blocking some of the side light that I think would have added to the measurements of 16" and deeper.



I have primarily ran the lights 10 inches off the canopy for the last while at .7amps so we will start with those stats.

Running the LED's at 0.7 amps I'm running 459 actual watts
PPFD
10" 900
12" 775-810
16" 610
24" 480-500

Running at 0.82amps is using a total of 568W from the wall
10"-1175
12"-980-1000
16" 815
24" 550

Running at 1.5amps ( I messed up and only took 2 measurements)
12"=1600
16"=1470
Running them all out at 2.1amps is running 1478W at the wall
12"=2250
16"=2100
24"=1160

At the 0.82 amp setting I can easily run the canopy at 10" without the canopy leafs going over 82 degrees. Ive been running 10" at 0.70 amps @ 460W for a while now.


What do some of you pro's get out of that? What does a plant need ppfd wise in flower? A low and a high end amount is what I need to find out. All of my readings are pretty average of readings testing all over under the light.
From the looks of the numbers would you guys say I put together a good light?

 

[fanleaf]

I may take some 1amp measurements as well.

 

[Graytail]

Icemud will know better, but from what I've read, around 500ppfd gets you the highest grams/watt and is considered a sort of minimum amount of light, and 1500ppfd is at saturation levels without a perfect environment and CO2.

You definitely put together a good panel!

My guess was a bit high, it seems. At 1000 watts you have ~1000ppfd. Nice! It does look like your 24" measurements are distorted though - they should have the same ratios at all distances, ie, 1500ma at 24" should be twice as much as 700ma.

 

[fanleaf]

Icemud will know better, but from what I've read, around 500ppfd gets you the highest grams/watt and is considered a sort of minimum amount of light, and 1500ppfd is at saturation levels without a perfect environment and CO2.

You definitely put together a good panel!



My guess was a bit high, it seems. At 1000 watts you have ~1000ppfd. Nice! It does look like your 24" measurements are distorted though - they should have the same ratios at all distances, ie, 1500ma at 24" should be twice as much as 700ma.

That will be great if a ppfd of 500 is decent. Heck I'm doing more than that at only 0.7amps. That would be awesome if I'm showing sufficient numbers at 0.7amps for 459W for the whole area. Let's see what Icemud says.


My 16 and 24 inch readings are probably low readings because I was trying to work with the plants in there

 

[fanleaf]

Also. Im not sure if Ill ever run them 24 inches up just because canopy temps at 10 inches stay so low.

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[Graytail]

Also. Im not sure if Ill ever run them 24 inches up just because canopy temps at 10 inches stay so low.

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True, but it also defines the depth of your canopy, and that can amount to a lot of yield.


[Edit] Ah! That reminds me of a visual.

If your tops are 2 feet from the lights ... then another 2 feet is twice as far.

If your tops are 10" from the lights ... another 10" is twice a far - your canopy depth sucks.

You want them farther from the lights to get a deeper canopy.

 

[fanleaf]

True, but it also defines the depth of your canopy, and that can amount to a lot of yield.


[Edit] Ah! That reminds me of a visual.

If your tops are 2 feet from the lights ... then another 2 feet is twice as far.

If your tops are 10" from the lights ... another 10" is twice a far - your canopy depth sucks.

You want them farther from the lights to get a deeper canopy.

How does canopy depth suck at 10" I dont understand because with not just 1 light hanging in the center but Leds at 1 per square foot or more it seems penetration wouldnt be a big issue because of the coverage. Can u explain how it would suck less at a further distance?
Just seems to me that if i can get the tops as close as 10 inches with no problems that that allows me to run lower power and still get good ppfd at 16 and 24 inches. The alternative would be to set at 24 inches above canopy and double my used power to get the ppfd up at 36 inches or so ( halfway down the plants or so). Im confused lol

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[Graytail]

That's why I tried to draw a picture. Look at your own numbers. They're showing half the light at twice the distance. So if the distance is 24 inches from the tops, you have another 24" before you reach half. If the distance is only 10 inches, you only have another 10" of depth before you reach half intensity.

One canopy is 24" deep at half strength - the other is only 10" deep. One will yield much higher.

The canopy gets squashed thinner as you move it closer to the lights.

 

[fanleaf]

That's why I tried to draw a picture. Look at your own numbers. They're showing half the light at twice the distance. So if the distance is 24 inches from the tops, you have another 24" before you reach half. If the distance is only 10 inches, you only have another 10" of depth before you reach half intensity.

One canopy is 24" deep at half strength - the other is only 10" deep. One will yield much higher.

Oh SHIT! I see what you mean now. Holy crap man. I need to be running a bit more juice than 0.7amps and further from the canopy and that will for sure increase yield. I'm going to measure how tall my plants are and figure that out for a good canopy distance. YOUR THE MAN! I bet running them at about 14-16 inches above and about 1 amp will be a good spot. While I'll be running a bit more juice it will also increase my coverage area because of raising the lights. I need to do some calculating lol.

 

[Graytail]

 

[fanleaf]

So, I didn't like what you brought to my attention so I figured being lazy was done so I moved the plants. Raised the light and tested a few combos.
Running 828W I'm now getting a ppfd of 1075 at 24 inches.

For the heck of it I tuned the light to 1000W on the money to see exactly what it does at 1kw and get 1420 at 24 inches.

I raised the lights to 15 inches above canopy and set to 828W. If I remember right the ppfd at 14-15" canopy is now 1425 give or take 25.
So for now I've adjusted to 1425 at canopy and still seeing 650 at the bottom of canopy.

 

[Graytail]

Heheh, it's pretty cool to have a meter! A guy can really dial stuff in.

Keep an eye on 'em. 1500 umols is bright. And as you increase intensity, yield doesn't keep up, so if it was me I'd look for 500 umols at the bottom, and in your case that looks like 1100 or so at the top which is nice and safe. The transpiration and nutrient flow within the plant will ramp way up at 1500, and it may have trouble keeping up with itself.

 

[Graytail]

And hey, thanks for the numbers! I've been guessing and calculating for my own space, so this gives me some concrete numbers to work with. I've been looking at 700 watts to be a nice average intensity to run them at, with the option of going 50% higher. I figured that would get me about 1000ppfd at 700 watts and 1500 at 1000 watts. I was close!

+reps!

 

[TorturedSoul]

1500ppfd is at saturation levels without a perfect environment and CO2.

I have read the same thing, along with 1,700 or 1,750 µmol as a maximum for even the most light-loving equatorial sativas, and that only at around 86°F (as the temperature falls down towards 77°F, the plants are not able to use quite so much light, IIRC). But there seems to be some debate about whether or not those numbers are overkill.

It does look like your 24" measurements are distorted though - they should have the same ratios at all distances, ie, 1500ma at 24" should be twice as much as 700ma.

Are you taking efficiencies of the hardware into account? My reading (and knowledge level) is woefully small, but I get the feeling that the efficiency of a COB varies; that there is a "sweet spot" in terms of how much power is fed - and that the spot differs among the different brands/models of COBs - and that efficiency falls as the input power rises from that amount. IOW, that one would not expect the resulting rise in illumination to be linear. (But I could be wrong, as I am still so ignorant in terms of LEDs.)

And as you increase intensity, yield doesn't keep up

Ah, but it does rise... to an extent (below a certain maximum light level, of course). The amount of power being fed the COBs is easily adjustable - the size and configuration of the space may or may not be. IOW, it might be easy for him to increase his (potential maximum) yield with the turn of a knob, even though the electrical efficiency of the grow would fall... but somewhat more difficult to increase the yield by enlarging the space (if increasing the space was, itself, difficult). Kind of like walking being more efficient than flying - but you can fly a lot farther in a day. Or... something?

Hey, fanleaf, if you're seeing a marked drop in light intensity down in the canopy, have you thought about moving the sources? Maybe keep the bulk up above, but move some down into the canopy (possibly one in each corner, angled towards the center and slightly downwards? It looks like some of the HID grows I've seen where the bulbs were within the canopy seemed to be the most efficient. Those were "bare bulb" (no reflector) setups, so the bulbs' light traveled out in a 360° pattern - which is not possible with LEDs, of course - but perhaps you could gain some yield by increasing the light levels down below (assuming it need not come at the expense of reducing the intensity up top)?

BtW, you are running multiple sources of illumination... How are the light levels between them? Are you seeing any significant drop-off, or do you have things dialed in enough that - at a point between multiple illumination sources where you are farthest from each - the drop-off of each of the multiple sources is able to combine to, together, still provide plenty of intensity? That "third-light" effect thing?

 

[fanleaf]

Are you taking efficiencies of the hardware into account? My reading (and knowledge level) is woefully small, but I get the feeling that the efficiency of a COB varies; that there is a "sweet spot" in terms of how much power is fed - and that the spot differs among the different brands/models of COBs - and that efficiency falls as the input power rises from that amount. IOW, that one would not expect the resulting rise in illumination to be linear. (But I could be wrong, as I am still so ignorant in terms of LEDs.)

LED efficiency shouldn't come in to play there. What Graytail is talking about is that the drop in intensity of light is linear at one set power. So ppfd at 20 inches will be half of what the ppfd is at 10 inches at the same power setting. That is true and that's why it makes absolute sense to change my setup a bit. Either keep current low like I have been but add some side light or raise canopy level and increase intensity so the linear drop in ppfd isn't cut in half every 10" but maybe 16 or 18 inches instead.

Hey, fanleaf, if you're seeing a marked drop in light intensity down in the canopy, have you thought about moving the sources? Maybe keep the bulk up above, but move some down into the canopy (possibly one in each corner, angled towards the center and slightly downwards? It looks like some of the HID grows I've seen where the bulbs were within the canopy seemed to be the most efficient. Those were "bare bulb" (no reflector) setups, so the bulbs' light traveled out in a 360° pattern - which is not possible with LEDs, of course - but perhaps you could gain some yield by increasing the light levels down below (assuming it need not come at the expense of reducing the intensity up top)?

I have today thought about this. My conclusion is that running these LED's down in the 0.7amp range uses only 450W +- in my entire area and has fantastic efficiency and great ppfd numbers from the top of canopy down midway before the numbers fall too much. So my thinking is that it may be far more efficient to add something like 1 cob in each corner 2/3rds down the plants pointing inwards about 45 degrees running at low current as well. That may make a very very high yield per watt situation.

BtW, you are running multiple sources of illumination... How are the light levels between them? Are you seeing any significant drop-off, or do you have things dialed in enough that - at a point between multiple illumination sources where you are farthest from each - the drop-off of each of the multiple sources is able to combine to, together, still provide plenty of intensity? That "third-light" effect thing?

The lights up top were carefully placed very evenly where they are. At 8 inches below the light reflectors and down there is very very little fluctuation in the light numbers, they blend together very well at 8 inches and down from there. That was my main goal and the reason that there is never an LED above the plants that is further than 9 inches from another LED. Anything 8 inches and closer to the LED's is where they don't blend together well and I see the readings fluctuate.

 

[TorturedSoul]

LED efficiency shouldn't come in to play there. What Graytail is talking about is that the drop in intensity of light is linear at one set power.

Ah, okay, perhaps I misunderstood him. He mentioned that 1,500 ma should be be twice as much as 700 ma (or 750, I don't remember specifically), which caused me to think that he was meaning that, in a graph with power level on one axis and light output on the other, the line across the graph ought to be straight (but at an angle, of course), linear.

The lights up top were carefully placed very evenly where they are. At 8 inches below the light reflectors and down there is very very little fluctuation in the light numbers, they blend together very well at 8 inches and down from there.

Sounds (reads) awesome!

 

[Icemud]

So heres some numbers!!! I have no idea what ppfd is ideal but I made a bunch of measurements and here they are. Maybe some of you that know what are good enough values can tell me how I'm lookin here.

Let me also say that I think my readings would have been a bit higher but with plants in there it was kind of blocking some of the side light that I think would have added to the measurements of 16" and deeper.



I have primarily ran the lights 10 inches off the canopy for the last while at .7amps so we will start with those stats.

Running the LED's at 0.7 amps I'm running 459 actual watts
PPFD
10" 900
12" 775-810
16" 610
24" 480-500

Running at 0.82amps is using a total of 568W from the wall
10"-1175
12"-980-1000
16" 815
24" 550

Running at 1.5amps ( I messed up and only took 2 measurements)
12"=1600
16"=1470
Running them all out at 2.1amps is running 1478W at the wall
12"=2250
16"=2100
24"=1160

At the 0.82 amp setting I can easily run the canopy at 10" without the canopy leafs going over 82 degrees. Ive been running 10" at 0.70 amps @ 460W for a while now.


What do some of you pro's get out of that? What does a plant need ppfd wise in flower? A low and a high end amount is what I need to find out. All of my readings are pretty average of readings testing all over under the light.
From the looks of the numbers would you guys say I put together a good light?

I'm at work so I can't go into detail, but research on different cannabis strains was done, and it was determined that the optimal PPFD for cannabis is 1500 umol/m2/s-1 WITH supplemental CO2.

Now the key word is WITH SUPPLEMENTAL CO2.


photosynthesis rate is a factor of 3 main measurements... available co2, PPFD and VPD (vapor pressure deficit) If all of these 3 things are at optimal levels, then cannabis will be at optimal photosynthesis. If one of these factors is limited, then the max rate of photosynthesis is much less, therefore....


IF YOU ARE NOT using CO2, then the most PPFD you really want to go is around 1000 umol/m2/s-1. Since CO2 are broken apart in the process, if you don't have enough co2, then its quite obvious increasing light will not make a faster rate.

Most home growers and LED enthusiasts shoot for around 800-1000 umol/m2/s-1.

Ive found other light loving plants such as tomatoes have a minimum optimal DLI of around 22, which is the minimum accepted DLI for optimal conditions, therefore 22 DLI translates into roughly 510 Umol/m2/s-1 at 12/12 schedule.. .


So ideally if not using CO2, you want to stay between 500-1000 umol at the top of your canopy, across the ENTIRE canopy, not just directly centered under the panel.

Now with that being said, any light lower than 500 umol, still will flower cannabis, but it wont be at optimal levels, density and may create airy buds. Also with potency being related to intensity of light, a higher intensity will produce a more potent product.

Also, with more intensity, you will get more yield, but your gram/watt will go down. The lower the intensity, the higher the gram per watt generally.

 

[Graytail]

Actually, according to the inverse square law, intensity should drop to 1/4 at twice the distance. Readings, however, are proof of circumstances in this particular setup.

What I was referring to is the linear relationship of power to intensity. If you double the power, umols at the same distance should be double. And no, I didn't account for driver loss or the change in emitter efficiency as current drops, and it wouldn't be a linear line, no. The 3590s are FAR more efficient at 350ma than 2100ma.

 

[fanleaf]

I'm at work so I can't go into detail, but research on different cannabis strains was done, and it was determined that the optimal PPFD for cannabis is 1500 umol/m2/s-1 WITH supplemental CO2.

Now the key word is WITH SUPPLEMENTAL CO2.

photosynthesis rate is a factor of 3 main measurements... available co2, PPFD and VPD (vapor pressure deficit) If all of these 3 things are at optimal levels, then cannabis will be at optimal photosynthesis. If one of these factors is limited, then the max rate of photosynthesis is much less, therefore....


IF YOU ARE NOT using CO2, then the most PPFD you really want to go is around 1000 umol/m2/s-1. Since CO2 are broken apart in the process, if you don't have enough co2, then its quite obvious increasing light will not make a faster rate.

Most home growers and LED enthusiasts shoot for around 800-1000 umol/m2/s-1.

Ive found other light loving plants such as tomatoes have a minimum optimal DLI of around 22, which is the minimum accepted DLI for optimal conditions, therefore 22 DLI translates into roughly 510 Umol/m2/s-1 at 12/12 schedule.. .


So ideally if not using CO2, you want to stay between 500-1000 umol at the top of your canopy, across the ENTIRE canopy, not just directly centered under the panel.

Now with that being said, any light lower than 500 umol, still will flower cannabis, but it wont be at optimal levels, density and may create airy buds. Also with potency being related to intensity of light, a higher intensity will produce a more potent product.

Also, with more intensity, you will get more yield, but your gram/watt will go down. The lower the intensity, the higher the gram per watt generally.

Thank you very very much. I understand what you are saying. I do have a question though. Looking at my numbers and the back and forth between me and Graytail you an see where when I'm running the lights only 10" above canopy at .82amps I'm getting a ppfd of 1000 at 12 inches which will be a ppfd of 500-550 at 24 inches down from the top of the lights but only 12 inches down into the canopy my best bet is to raise the lights more from the canopy and increase power a bit. Lets say for example if I were to move the lights up 16 inches from canopy and tune the lights to provide a ppfd of say 1100 at the canopy top which will then still have roughly a ppfd of 550-600 16 inches down from the top of the canopy? If I understand right it will increase yield for 2 reasons. #1 because I'm simply using more wattage but also because I'm getting better ppfd further down the canopy?