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Post by deanna on Sept 24, 2017 20:42:31 GMT -5
I'm revisiting the PUR concept as it relates to the Grobeam 600's in a FW planted tank.
I can't find any PUR values for the Grobeams and I know that PUR is more meaningful than PAR. So, I assume that eyeballing the spectral curves will have to do, with the idea that having high shoulders on the curve means that PUR values are high since blues and reds are much higher than the green-yellow region.
However, when we think about 6500K as being natural sunlight, the spectral curve is very high in that green-yellow region which seems to contradict the concept of PUR.
Is this correct?
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Post by Carl on Sept 25, 2017 8:59:26 GMT -5
The GroBeam is meant to mimic as closely as possible the noontime tropical sun, this includes as PAR spectrums (including green). It is not intended to mimic the key spectrums used by many hydroponic growers. As for PAR vs PUR, both are important, but the way to look at it is that PAR is the energy needed by plants and PUR is the more efficient energy. This makes PAR the starting point.  Reference: www.aquarium-pond-answers.com/2012/03/pur-vs-par-in-aquarium-lighting.htmlCarl |
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Post by deanna on Sept 25, 2017 12:45:16 GMT -5
So, as I look at the curve, it would seem that perhaps half of the 61 PAR value in the Grobeam 600 is non-PUR or, in a sense, wasted light for growth purposes. Is it then correct to say that the PUR value for the Grobeam 600 is about 30, assuming my estimate of half of the PAR is accurate, and most of that 30 is blue spectrum?
If I want to increase bushy growth in FW stem plants (reducing internodal length), it seems that I would be better supplementing the Grobeam 600 (which has very little red spectrum) with the AquaRed, since blue light is known to trick FW plants to seek better light, causing leggy growth, and red light does the opposite. So, I’m inclined to order the AquaRed Flexi-LED.
Is my thinking sensible?
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Post by devonjohnsgard on Sept 25, 2017 12:50:52 GMT -5
The GroBeam does have a good amount in the growing ranges, but also does gave some warmer color, which help green to pop. The green and yellow helps visually.
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Post by devonjohnsgard on Sept 25, 2017 12:57:51 GMT -5
All the color is used collectively as well, which is why a full spectrum is recommended. Lengthy growth is due to not enough or not strong enough light. The high blue peak in the GroBeam, with the high amount of red will give a high amount of growth power. Green and yellow has growth power as well, just not as much. All of them working together is best for the plant.
Plants I've grown and all the pictures using the GroBeam have bushy growth. I wouldn't use the Super Red LED light for trying to grow. It will give a real red appearance to the tank. I haven't seen the GroBeam not provide good growth. If you wanted more read, but to much, consider the Color Plus. Busyness is also controlled by the amount of Co2 and Ferts used.
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Post by deanna on Sept 25, 2017 16:35:56 GMT -5
It's a little frustrating seeing the leggy cabomba, anacharis and rotala. I was reaching for a color spectrum solution, but maybe it's not there (certainly don't want a red tank). I have two Grobeam 600's on a 29 gallon (plenty of light), CO2 at 30-35 ppm (plenty) and EI dosing of ferts. Overall good growth and health in most plants (dwarf sag spreading like wildfire and nice juicy reineckii). Would just like to see bushier stem plants.
Thanks
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Post by Carl on Sept 26, 2017 9:34:09 GMT -5
So, as I look at the curve, it would seem that perhaps half of the 61 PAR value in the Grobeam 600 is non-PUR or, in a sense, wasted light for growth purposes. Is it then correct to say that the PUR value for the Grobeam 600 is about 30, assuming my estimate of half of the PAR is accurate, and most of that 30 is blue spectrum? If I want to increase bushy growth in FW stem plants (reducing internodal length), it seems that I would be better supplementing the Grobeam 600 (which has very little red spectrum) with the AquaRed, since blue light is known to trick FW plants to seek better light, causing leggy growth, and red light does the opposite. So, I’m inclined to order the AquaRed Flexi-LED. Is my thinking sensible? Generally it is the blue light that creates more bushy growth (which the GroBeam Daylight has a good amount of). Adding a Flexi Blue or even Fiji Blue would add more Reference: www.americanaquariumproducts.com/AquariumPlants.htmlBTW, all light spectrums create growth, it is more a matter of efficiency with PUR  Above from: aquarium-digest.com/2010/04/11/led-aquarium-lights-lighting/QUOTE (from above article): "We’re also finding with along with just blue, it’s a combination of color, which will produce the most mass on a plant. We could say, lets just grow our plants under blue light, but this has shown negative impacts on plants, which is why full spectrum are recommended, at least for plant growth."Carl |
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Post by devonjohnsgard on Sept 26, 2017 11:45:31 GMT -5
How are the LED mounted, can they be lowered?
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Post by deanna on Sept 27, 2017 15:26:00 GMT -5
Thanks, Carl: Yes, I've seen it both ways where absence of blue increases internode length and/or where absence of red increases internode length. My thinking was that, since the GroBeams already have high blue throughput and seem to be weak on the reds, that adding red would be more effective. I don't know, without testing, in my particular situation.
Thanks, Devon: the lights, right now, are mounted about 1 inch from the water surface, pointing straight down in the center of the tank, but are on top of a 1/8" glass cover. So, I know I'm losing the standard 13% loss of light through that thickness of plate glass. I don't know if it affects any particular wave lengths more than others, though. For example: maybe blues and reds are reduced more than the 13% of the PAR value. I do intend to build a canopy that would eliminate the glass cover.
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Post by Carl on Sept 27, 2017 20:11:15 GMT -5
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Post by deanna on Sept 27, 2017 22:59:44 GMT -5
Thanks for that reference link. I've been looking around the Internet for spectral curves on white light transmission through .125" thick glass, but could find none. I know total PAR is about 87%, but don't know what blue spectrum is. Acrylic is 92% transmission, polycarbonate 87% (like glass). Sent a note to TMC asking about the impact that standard plate glass, in different thicknesses, has on their LEDs since LEDs crowd most of their energy into very thin nm ranges. They've been good, in the past, about responding. If I get any info of consequence, I'll post it. Should their blue nm spread be in one of the dips of plate glass, that would dramatically hamper the PUR on the blue side. People might blame the GroBeams when, in fact, it's the glass filtering effect. Rather than try to push more blue or red through the glass, I'm going to try removing the glass to see what happens.
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Post by deanna on Sept 28, 2017 23:08:18 GMT -5
Devon,
What do you find to be the optimal distance between the water surface and the bottom of the acrylic lens on the GroBeam?
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Post by devonjohnsgard on Sept 29, 2017 10:52:51 GMT -5
Devon, What do you find to be the optimal distance between the water surface and the bottom of the acrylic lens on the GroBeam? I've had the height from right above the water to about 8 inch up. My major concern is spread. When the light is low, you can actually see the spread and depending on the tank, the light is not high enough. I've not seen difference in grow in this range and I have the same plants in different tanks with different mounting. I prefer the 3-6 range, and it helps to be able to work in the tank with the light still on. When I've set them on the glass, I've made sure to raise them up about another inch to help with spread. |
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