Discussion in 'DIY' started by rygh, Aug 29, 2016.
That is a lot of light for two LEDs. I like it.
It is 84W (at the LEDs) of LED.
But yes, it was quite a bit bit brighter than I expected.
Gut feel was that it was not too different from a Kessil AP700, which is supposedly twice the power.
Do you have an AP700 to compare? Or par numbers?
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No, but I have seen them in action.
My hope is to get some recent PAR number from Dick. I watched him measure it, so hopefully can
do similar and get a reasonable comparison.
Were you able to get the par readings?
These are measured at "my max" which is 700 mA for mains and 350mA for secondary, which is
actually HALF of the max power the LEDs can handle.
PAR in the air < 3" from Lumia = maxed out meter at 3,000
PAR in the air, 11" from Luma = 500 under LEDs up to 700 between LEDs.
LEDs are spaced 10" apart, so that peak was 5" from both.
Drops to 400 about 6" out from under LED, so pretty uniform.
PAR in the water, at 1" depth (13" from LED) = 300 to 500. Varied by position same as above.
PAR at 6" (18" from LED)= 220-300 or so.
I was quite happy about how uniform it seemed to be at 6" down.
Frag racks are at that level.
PAR at 12" (25" from LED, the bottom) = 100-200
Surprised it did not drop off more.
I have been running the lights at pretty close to half rate on PWM. (Technically 1/4 of true max)
At 1/2 power, PAR at 6" is 150-200.
I did not really expect it to be that linear, but I am a bit surprised it is not closer.
For my main tank, I had to keep turning the lights down, or things would bleach out.
At half depth, where most of the coral is, PAR in main tank is now about 75.
Yet some of the same corals are doing really well in the 200 range in the fuge.
Those are really good numbers. @Vhuang168, how do those numbers compare with what you've found with your ap700? @rygh's spacing between his two luminas are very similar to the ap700 right?
PAR is not the end all of light measurement. What wavelengths are important too.
In air @12"650 under 1 puck
Between both 715
Under 1" water (@13" from light) 460
@6" under water (19") from light 290 - not quite under the puck but close.
@12" under water (25" from light) 230 - this one was tough, couldn't get it right under a puck.
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PAR numbers sound pretty similar to AP700.
That surprises me quite a bit. The AP700 is supposed to be almost twice the power.
Yes, PAR meter cannot measure LED wavelengths well.
But both should have issues since they have a lot of UV and such, and off by 2X is hard to believe.
Some other notes:
I measured the wall power when all-on. 86W
Good power factor as well. Not that it really matters, but confirms good power supply.
I played around with taking the lenses off.
Definitely reduces PAR at water level. It spreads very quickly. Might work well if LEDs were about 4" from water.
I also did a tight spotlight. Lens is adjustable. Tons of penetration, but of course, a narrow beam.
You would need a lot of Lumias, but I think it would work great for a deep tank.
Seems like around 70 degrees is idea. +/-a lot though. Really hard to measure that.
So when you took the lenses off the light just went everywhere and the par went down? The lumina sales rep guy I talked with said I didn't need the lenses. Did you get the ones from ledgroupbuy or different ones?
I bought them from ledgroupbuy.
The diodes have 120 deg lenses on them, but they are tiny and far from perfect.
Lenses block about 10% of the light due to simple losses.
Light that goes straight down casts larger shadows.
Light at an angle will be absorbed by the water more before it hits the bottom due to extra distance.
Lots of light shining out into the room can be seriously annoying.
Do you plan on a fixture right against the water that you lift up for maintenance?
Lenses cost extra.
So do you "need" them? - No. Do you "want" them? - Probably.
Most off the shelf fixtures have lenses.
Light that goes straight down will cast larger shadows? I would think a single light source (i.e. a Lumia) would create larger shadows as a wider beam since everything in the light of sight will shade things. Which IMO is one of the largest issues with many of the current LED setups, they have clusters to reduce color banding, but then that tends to make a single light source, even when you get things like the Radion setup, you get 2 light sources, compare this to a T5 setup which might have a 2-4 foot long light source that's a few inches thick, or a metal halide that could have a as large as a 19" x 19" light source with the largest of reflectors.
Someone really needs to make a setup that moves their LEDs across the tank like people do with metal halides
Yeah, it all depends on how many Lumia's you use.
For my main tank setup, I was assuming 9 or so all overlapping.
In that case, the wider beams get under the various coral and rock structures, so you get very few shadows.
If you had tighter beams, you do not have the angle to get under structures, so more shadows.
Agree, a few single point sources will certainly cause a shadow issue.
That said, some people like shadows. It does add contrast and interest.
Why move lighting across the tank?
Note that it would be pretty trivial to do electronically, just expensive.
You would have different PWM controls for each set along the tank, and just turn sections on/off as you please.
I think he is talking about physically moving the lights so that it is coming from different angles throughout the day so you get less shading since the point sources will be in different parts of the tank.
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Exactly what Vincent said.
I imagine a small frag tank, maybe lit by a single XR15 or something, sure the light might have sufficient "coverage" but the fact of the matter is that most of your corals other than "flat" ones are going to only get a lot of illumination from one angle where the other side will be "meh" if you could move across the tank you basically mimic the Sun where you have corals getting hit by the angle that the Sun subtends as it goes from one side of the "sky" to the other. Of course mix it up with some standard lights that illuminate the whole tank uniformly (similar to what the sky does), but maybe have one super bright LED "cannon" that moves across at different angles as moves (parabolic arc a little overkill? )
Of course from the point of view of a relatively small frag tank you could simply put two lights on either end (maybe one in the middle) pointing at angles into the water and simply have them go on at different intervals to mimic the different directions of light. The downside is that while you don't need to physically move a light, you'd need to invest in 3 times the hardware.
Although what Mark is doing with 9 of them spaced out should effectively do the same thing.
I'm just brainstorming different ways to effectively light a tank... don't mind me
Interesting idea. Might be able to do it with mirrors on a stepper gear motor.
As a bonus, your tank would look dramatically different at different times of the day.
That could be good or bad though.
Quick 3 month update on the lights:
I am VERY happy with these lights.
I have a few things in the fuge:
Some softies that are growing well unless being eaten by my filefish.
Some red macro algae, growing like crazy, even though it is off to the side.
And um, a fair bit of Cyano. Side issue of course.
But key: the Coraline is growing like crazy!
I never had that kind of growth rate under my other DIY LEDs.
It may not be quite MH growth rate, but it is great compared to what I am used to.
Same water. Similar PAR.
My other LEDs are almost completely Royal Blue + Cool White. A tiny bit of neutral white and red is all.
So it must be the extended spectrum.
The only issue:
I am getting a lot of condensation on the lenses.
I sealed those pretty well, but I worry moisture is getting up into the LEDs.
I might have to add an acrylic layer or they may not last so long.
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