DIY LEDs - The write-up

[lpsouth1978]

I don't know what PAR should be with LEDs (or if anyone does) but IMHO those are 2-3 times what they need to be.

Wouldn't the ideal par be the same regardless of the type of lighting being used. Par is a measure of the light that is usable for photosynthesis. that should not change based on the type of lightin being used. Of course, any one is welcome to correct me if I'm wrong.

I have never heard a deffinite value that is ideal, but it seems to me that 1/3 of the values I got would put it at 90 PAR on the sand. That seems like a pretty low number to me. I mean 1 standard 60w lightbulb in my apartments reads at 100 PAR. I don't know of a single standard light bulb that can sustain SPS or most other corals longer tan 5 minutes.

Again, I am no expert, but your estimate seems a bit low. I was thinking closer to 180 PAR on the sand was a pretty good number to shoot for. If I am wrong please let me know.

 

[jcgd]

Wouldn't the ideal par be the same regardless of the type of lighting being used. Par is a measure of the light that is usable for photosynthesis. that should not change based on the type of lightin being used. Of course, any one is welcome to correct me if I'm wrong.

I have never heard a deffinite value that is ideal, but it seems to me that 1/3 of the values I got would put it at 90 PAR on the sand. That seems like a pretty low number to me. I mean 1 standard 60w lightbulb in my apartments reads at 100 PAR. I don't know of a single standard light bulb that can sustain SPS or most other corals longer tan 5 minutes.

Again, I am no expert, but your estimate seems a bit low. I was thinking closer to 180 PAR on the sand was a pretty good number to shoot for. If I am wrong please let me know.

I think something in the hundreds at the sand would be ideal. Instead of dimming the fixture, can you raise it? Raising the fixture will give you more consistent par levels throughout the tank.

 

[lpsouth1978]

I think something in the hundreds at the sand would be ideal. Instead of dimming the fixture, can you raise it? Raising the fixture will give you more consistent par levels throughout the tank.

I can easilly raise the fixture.

 

[brassmonkyballs]

PAR Readings

PAR Readings

Thought some folks might be interested in some PAR readings from my build. Recap:

120G 4x2x2 Oceanic Tech tank
36" fixture
18 Cree CW
6 Cree NW
50 Cree RB
MW HLG 120-42B running the whites and 6 RBs
MW HLG 185-42B running 44 RBs

THERE ARE NO OPTICS ON THIS BUILD

Overall I am very happy and i think in the perfect range and in fact all my corals are responding very nicely...no burnout or bleaching! With optics there is no doubt the top of the tank would be too high. Thats not to say I couldn't add some 60 degree lenses on the very front row and the ends to focus a bit more on the sand and the sides of the tank.

The bottom row of measurements are on the sand next to the glass with the end readings in the corners so well away from the fixture. The ends of the center and top rows were taken just outside the fixture ends but the middle is under the fixture. I also am led to believe that the sensor reads the RB ~20% low due to the narrow spectrum but who knows.

Here they are

 

[brassmonkyballs]

For those that have experimented with the HLG series. Has anyone figured out how to use less current? Say the output is 48 volts 3.9 amps. What if I only want 2 string at 1 amp each and the drop will only be around 39 volts?

TIA

Aside from buying a smaller driver the easiest thing to do is install a hard stop on your dimmer knob....assuming you're manually dimming that is....dial it up to where you want and drill/install a small screw next to it to physically stop the Pot. Sounds crude but it'll work fine and can be done cleanly. Then when you want to expand remove the screw.

 

[lpsouth1978]

brassmonkyballs,

Thanks for the info. Those numbers seem to match VERY closely to the numbers I got from my fixture.

 

[brassmonkyballs]

brassmonkyballs,

Thanks for the info. Those numbers seem to match VERY closely to the numbers I got from my fixture.

Sure thing. Whats surprising to me is your readings are not significantly higher. If I read that right you have a 3G Pico cube with 12 LEDS.....I probably would have put 4 on it....I ran 12 on a 14g cube for a year as a test on coral growth and had it very dimmed.

How high is the fixture and I wonder how much you are lighting around and outside your tank?

By the way...I agree with your thoughts on PAR readings in general. PAR is PAR and it doesn't matter the source and LED PAR is the same save the potential for low readings due to narrow spectrums like the RBs....then again I'm not an expert but it all makes sense.

I think your PAR readings are fine. Put a nice Acro in there and show everyone how you can grow SPS in a real nano

Any pics of the little bugger would be cool.

 

[peiloy3196]

peiloy3196; Groan... Doing stuff in plastic boxes is so tempting but it's a, um, not good idea.

Whenever electronics are put into plastic it's always fire-proof. It's a type that will char and smoke but will not catch-fire itself. Plastic storage bins are made from 'cheap' plastic that has no fire rating - except for maybe the number of BTU's it will provide the fire it's in....

Another problem is that a plastic box begs to have things stacked on it. So someone makes a system and it's marginal temp-wise. 95% of the heat leaves out the top of these boxes. You see where this is going? After the focus on the box is lost a year down the road someone stacks something on top of it.... ====> "The fire report shows the fire began in the vicinity of the aquarium."

The other issue is that everything may be fine now. What happens if something changes. Your tested situation may go right out the window. An example would be a driver that has an internal failure that doesn't cause its own circuit protection to trip!

I am currently working with an RC member whose ELN is running so hot he can't touch it... What happens when that happens to the plastic mounted driver the day you leave on vacation?

I'd re-do your build in a metal, container of some sort. I know it sux..

Thanks for the advice Kress. Better to be safe than sorry. I took the drivers out of the project box and mounted them directly to my canopy until i can find an aluminium box.

 

[lpsouth1978]

Sure thing. Whats surprising to me is your readings are not significantly higher. If I read that right you have a 3G Pico cube with 12 LEDS.....I probably would have put 4 on it....I ran 12 on a 14g cube for a year as a test on coral growth and had it very dimmed.

How high is the fixture and I wonder how much you are lighting around and outside your tank?

By the way...I agree with your thoughts on PAR readings in general. PAR is PAR and it doesn't matter the source and LED PAR is the same save the potential for low readings due to narrow spectrums like the RBs....then again I'm not an expert but it all makes sense.

I think your PAR readings are fine. Put a nice Acro in there and show everyone how you can grow SPS in a real nano

Any pics of the little bugger would be cool.

You can check it out on my build thread. Here is the link. I have also posted a couple of pics of the light. The light is about 10 inches off of the water and there are no optics on it. I am sure that there is a lot of light that does not make it into the tank. It is an open top tank, no canopy.
http://www.reefcentral.com/forums/showthread.php?t=2027236

 

[jcgd]

That light is sick. What did you use for the heat sink?

 

[lpsouth1978]

That light is sick. What did you use for the heat sink?

I got the heatsink/fixture from nanotuners.com. I had to drill some holes in the top for the hanging kit, and one in the back for the wires.

 

[kcress]

Thanks for the advice Kress. Better to be safe than sorry. I took the drivers out of the project box and mounted them directly to my canopy until i can find an aluminium box.

Great to hear. :celeb2: I hope you can come up with a picture of your final rendition.

 

[Rhodes19]

Thought some folks might be interested in some PAR readings from my build. Recap:

120G 4x2x2 Oceanic Tech tank
36" fixture
18 Cree CW
6 Cree NW
50 Cree RB
MW HLG 120-42B running the whites and 6 RBs
MW HLG 185-42B running 44 RBs

THERE ARE NO OPTICS ON THIS BUILD

Overall I am very happy and i think in the perfect range and in fact all my corals are responding very nicely...no burnout or bleaching! With optics there is no doubt the top of the tank would be too high. Thats not to say I couldn't add some 60 degree lenses on the very front row and the ends to focus a bit more on the sand and the sides of the tank.

The bottom row of measurements are on the sand next to the glass with the end readings in the corners so well away from the fixture. The ends of the center and top rows were taken just outside the fixture ends but the middle is under the fixture. I also am led to believe that the sensor reads the RB ~20% low due to the narrow spectrum but who knows.

Here they are

Nice job on the par readings. That's a good amount of light.

 

[TheFishMan65]

I mean 1 standard 60w lightbulb in my apartments reads at 100 PAR.

I don't think so it was probably 100 lumen.

Let me thry and summarize this page which is worth the read.
PAR is not really PAR
PAR (Photosynthetically Active Radiation) is the light in the 400-700nm range. You could have 1000 PAR all in red and the Corals would do poorly, but the Algae would do great if I understand all this. The algae is adapted to warmer light and the corals to cooler.

So what you really care about is PUR (Photosynthetically Useful Radiation). And different living organism have different ranges.

I also am led to believe that the sensor reads the RB ~20% low due to the narrow spectrum but who knows.

It depends on the sensor (or maybe the meter I don't understand the difference between the sunlight and electric version) but maybe even 40% low. Look at this graph from Apogee. The response for the 450 range is 70%. So I think if you have a reading of 100 from just royal blues your real value is closer to 100 / 0.7 = 143.

Now I have read for MH 500 on the surface and 100 on the sand, but if we are 40% low (remember CW have a lot of blue) then that might mean 350 on the surface and 70 on the sand. I really think with 1000 surface 270 sand you will bleach your corals.

 

[brassmonkyballs]

I don't think so it was probably 100 lumen.

Let me thry and summarize this page which is worth the read.
PAR is not really PAR
PAR (Photosynthetically Active Radiation) is the light in the 400-700nm range. You could have 1000 PAR all in red and the Corals would do poorly, but the Algae would do great if I understand all this. The algae is adapted to warmer light and the corals to cooler.

So what you really care about is PUR (Photosynthetically Useful Radiation). And different living organism have different ranges.

It depends on the sensor (or maybe the meter I don't understand the difference between the sunlight and electric version) but maybe even 40% low. Look at this graph from Apogee. The response for the 450 range is 70%. So I think if you have a reading of 100 from just royal blues your real value is closer to 100 / 0.7 = 143.

Now I have read for MH 500 on the surface and 100 on the sand, but if we are 40% low (remember CW have a lot of blue) then that might mean 350 on the surface and 70 on the sand. I really think with 1000 surface 270 sand you will bleach your corals.

Right so PAR really is PAR in this discussion...we don;t have reds nor do our LEDs throw a lot of reds.....our LED builds, T5's, and MHs are really designed to operate in the PUR range.

As for the low reading theory...I don't know. i read somewhere that based on some testing someone concluded the readings were 20% low. 40% seems a bit much. Lets not forget that our MHs are throwing PAR spikes in the 450nm range as well and so therefore would be measured inaccurately as well.

I think the biggest reason for bleaching with LEDs is the common practice of putting twice an many LEDs as you need in the build and then putting tight optics on them. Seems everyone does it and has been doing it and will continue to do it....only to dim them down 40-50%. I do think with the common 50/50 mix adds to color loss....my initial little test rig caused several SPS to lose some color when 50/50...when I changed it to 2-1 they colored up in a month.

I really was going to go with 60 in my build but I got concerned about coverage and then when I finally decided on 2-1 RB-CW based on some smaller builds of mine I got concerned about having enough CW energy in the tank....so I increased it up to 74. Then after I built a 28 LED RB fixture for a friend as supplement to his T5's and saw how well it penetrated his 30" deep tank with no optics I knew I would not use lenses. I am currently very pleased by those PAR levels. Time will tell if my corals are as pleased

I still need to check out those links. Thanks for that info fishman!

 

[TheFishMan65]

I never really looked into MH so they may or may not have a similiar spectrum to LEDs. My understanding (maybe wrongly) was that they had quite a bit of the red end.

That article came to the conclusion that you do not need more than 1 watt of good LED power per gallon and don't go over 24 inches. I have 48 (XR-E 50/50) about 24 inches above a 75. With mix of 40 and 60 degree optics. I am running them at about 500ma and achieve 300 PAR on the surface. So I am probably a little over 1 watt per gallon. The Monti Cap I had under T8s bleached when I switched to LEDs.

I don't know the PAR number that we need for LEDs, but I really think that 1000 on the surface is more than is required.

 

[metamorphis]

Since power is much less of a concern, I'm toying with the idea of hanging a fixture very close to the ceiling and using narrow optics. I think this would be a notable aesthetic improvement on a rimless starphire setup.

Has anyone done this before? I'm thinking at least 40" off the surface. I prefer my lighting less blue than 90% of reefers, so I'm hoping coloration will be less of an issue. Hoping to use XM-L's.

Advice?

 

[kcress]

Since power is much less of a concern, I'm toying with the idea of hanging a fixture very close to the ceiling and using narrow optics. I think this would be a notable aesthetic improvement on a rimless starphire setup.

Has anyone done this before? I'm thinking at least 40" off the surface. I prefer my lighting less blue than 90% of reefers, so I'm hoping coloration will be less of an issue. Hoping to use XM-L's.

Advice?

Widmer did a nice one.

http://www.reefcentral.com/forums/showthread.php?t=1784873

 

[bhammer]

Wow, I didn't think I would make it, but I finally reached the end of this massive thread. Great job to the regulars for all their help and guidance.

I am in my initial research phase and think I would like to start laying out patterns in sketchup. My tank is a 280G that is 72X36X24. It is a wide tank.
Your thoughts and commentws are greatly appreciated.

Here's what I was thinking:

Using HLG-185-48 for the drivers.

130 Cree RB with 13 per string at 750ma with 10 strings and 5 strings per driver.

52 Cree CW with 13 per string at 1000ma with 4 strings on 1 driver

13 Cree NW with 13 per string at 1000ma with 1 string. Maybe add this to the CW driver or run seperate so I have control over the color balance.

Does my math look right for this setup?

Driver Output Voltage 48 48 48
Foreward Voltage (Vf) 3.5 3.5 3.5
Driver Output Wattage 3900 3900 3900
LED Maximum Rating 1000 1500 1500
LED Power Factor 75.0% 75.0% 75.0%
Max LEDs in String 13 13 13
LEDs Required 130 52 13
Strings per Driver 5 4 4
Strings Needed 10 4 1
Actual LED Count 130 52 13
Drivers Required 2 1 1

 

[jcgd]

Since power is much less of a concern, I'm toying with the idea of hanging a fixture very close to the ceiling and using narrow optics. I think this would be a notable aesthetic improvement on a rimless starphire setup.

Has anyone done this before? I'm thinking at least 40" off the surface. I prefer my lighting less blue than 90% of reefers, so I'm hoping coloration will be less of an issue. Hoping to use XM-L's.

Advice?

I'm doing a DIY LED build based off of this:
http://www.reef addicts.com
/content.php/70-LED-pendent-build

I'm using custom drivers, and will be running cool white XML for my main lighting and neutral white with royal blue XPG to add colour. 40 degree optics on the XML as the fixture will be about 6 feet off the substrate. My build is for a planted tank though, not a reef. But I wont be surprised if it can grow at the minimum softies. I'm using 28 XML at 2A and 24 XPG at 1000mA max over a 72x24x22 inch tank.