DIY LEDs - The write-up

[marcer]

I want to build DIY LED for 48"x24"x24" glass tank. I'm considering:

56 (8 strings of 7 ) or 72 (12 strings of 6) of RB XP-E at 700ma with +-12 FWHM Ledil optics
no or 14 CB XP-E at 700mA +-23 FWHM optic
14 XM-L (2 strings of 6) of CW at 2000ma +-18 or +-27 FWHM Ledil optics
14 XM-L NW at 2000ma - same optic as CW

I plan to use five 9.5"x24" heatsinks put together to create big 48"x24" heatsink hanged 20" over tank and place LEDs in independent triangular grids and control via PWM to Cat4101 drivers.

Do you think it is too much light for such tank? About 400W for 400 litres - 106gal. (rule of thumb)

 

[bamf25]

I want to build DIY LED for 48"x24"x24" glass tank. I'm considering:

56 (8 strings of 7 ) or 72 (12 strings of 6) of RB XP-E at 700ma with +-12 FWHM Ledil optics
no or 14 CB XP-E at 700mA +-23 FWHM optic
14 XM-L (2 strings of 6) of CW at 2000ma +-18 or +-27 FWHM Ledil optics
14 XM-L NW at 2000ma - same optic as CW

I plan to use five 9.5"x24" heatsinks put together to create big 48"x24" heatsink hanged 20" over tank and place LEDs in independent triangular grids and control via PWM to Cat4101 drivers.

Do you think it is too much light for such tank? About 400W for 400 litres - 106gal. (rule of thumb)

For what it is worth. I am doing leds for the same size right now. I will be running them about 6 or 7 inches over the water in an old MH fixture. I am running 26 XP-G cool/neutral whites at 1000 mA, 35 Royals with 4 blues at 700 mA for a total of 65 leds on 5 eln's. I am doing the linear thing with the leds mounted on 5 pieces of U channel (13 leds on each), and 2 or 3 120mm fans. The old MH has multiple fans vents, and an easy way to cover them. I am running no optics for now with only 7 inches above the tank, and stright linear on my colors like T5's would be. So I will have 3 rb bars and 2 white bars in about a 10 inch area. By being a modular setup, it should be easy to add more bars if needed.

 

[Saltwatercoral2]

I have a 75 gallon tank. 48 x 18 x 21. Corals will be LPS, Clams, Anenomies, and softies. How many LED's will i need?

 

[marcer]

For what it is worth. I am doing leds for the same size right now. I will be running them about 6 or 7 inches over the water in an old MH fixture. I am running 26 XP-G cool/neutral whites at 1000 mA, 35 Royals with 4 blues at 700 mA for a total of 65 leds on 5 eln's. I am doing the linear thing with the leds mounted on 5 pieces of U channel (13 leds on each), and 2 or 3 120mm fans. The old MH has multiple fans vents, and an easy way to cover them. I am running no optics for now with only 7 inches above the tank, and stright linear on my colors like T5's would be. So I will have 3 rb bars and 2 white bars in about a 10 inch area. By being a modular setup, it should be easy to add more bars if needed.

I want to have both LPS and SPS.

Big heatsink is advantage, with Rth only 0.44 °C/W per 150mm I have calculated the temperature should rise only 8.8 °C by 400W witout any fans.

 

[TheFishMan65]

marcer - IMHO you have too many LEDs
bamf - I like your numbers
Saltywatercoral - I have 48 over a 75.

My tank has them about 18 inches up mixed 40/60 lenses all XR-E 50/50 about 500 ma. I have 300 par at the surface and bleached every SPS I had 8 inches down.

 

[brassmonkyballs]

Thoughts on Optic Types

Thoughts on Optic Types

Wondering what thoughts are out there in types of optics. Not 40 vs 60 degree, etc., but the different makes and places to get them. There's some available as for XPE or XPG, these have to be glued on, then there's XRE types that snap on. These all seem to be $1.25 to $1.50 each. Then there's low cost versions available. Any opinions?

 

[wfournier]

Wondering what thoughts are out there in types of optics. Not 40 vs 60 degree, etc., but the different makes and places to get them. There's some available as for XPE or XPG, these have to be glued on, then there's XRE types that snap on. These all seem to be $1.25 to $1.50 each. Then there's low cost versions available. Any opinions?

Avoid those that have a flat round base close to the size of the star, they are a pain and now worth the trouble imho.

In my experience all of the clip on optics will fall off some LEDs so you are better off just gluing them on anyway. Just use small drops of epoxy so you can pop them off later if necessary.

 

[brassmonkyballs]

Avoid those that have a flat round base close to the size of the star, they are a pain and now worth the trouble imho.

In my experience all of the clip on optics will fall off some LEDs so you are better off just gluing them on anyway. Just use small drops of epoxy so you can pop them off later if necessary.

What about quality of the optics? Any to stay away from or pretty much a 60 degree is a 60 degree whether you pay $1.50 each or 25 cents?

 

[wfournier]

It's hard for me to comment on that, there are certainly some that have better documentation and appear to be higher quality if only in the way they are presented. Then again there are some that can be had for less than a dollar that look identical to those being sold by LED retailers for more $$. Whether looks are deceiving or not is a hard question to answer.

 

[vthondaboi]

Just a quick report on my PAR values and light setup.

250G 72x30x27.5
24 XPG CW - 1050ma driver
48 XPE RB - 700ma driver

No optics or shield. Lights are 3.5" from top of the tank.

1/3 way down - 300
2/3 down - 200
top of 2.5 inch sand bed - 90

300 seems like plenty of light to keep SPS. So why are people pushing it jus to bleach corals?

I plan to add optics to the RBs on the edges of the tank to help with spillover too.

 

[bamf25]

Just a quick report on my PAR values and light setup.

250G 72x30x27.5
24 XPG CW - 1050ma driver
48 XPE RB - 700ma driver

No optics or shield. Lights are 3.5" from top of the tank.

1/3 way down - 300
2/3 down - 200
top of 2.5 inch sand bed - 90

300 seems like plenty of light to keep SPS. So why are people pushing it jus to bleach corals?

I plan to add optics to the RBs on the edges of the tank to help with spillover too.

I am not sure. I think people have become so accustomed to the watts per gallon ideas of old, that it is hard to except these little LEDs can do so much with so little. I am putting 65 on a 120g and suspect it will be way more light than I will ever need. With so many people having to dial back their mA's or dim their lights, it should indicate we need to rethink how many led's are really needed. Or at least get more hard numbers on Par to see what we are really doing.

 

[TheFishMan65]

I think part of the problem was I read in several places and repeated 500 at the surface and 100 PAR at the bottom. The problem (from reading) is that PAr meter are not accurately reporting the blue. So PAR reading for LEDs need to be adjusted somehow.

 

[vthondaboi]

So are the PAR meters reading more PAR from the blue spectrums then they should?

When I cranked on the 24 CWs they blue almost 400W of PCs out of the water.

 

[wfournier]

So are the PAR meters reading more PAR from the blue spectrums then they should?

When I cranked on the 24 CWs they blue almost 400W of PCs out of the water.

PAR meters read a lower level from the blue spectrum than they should. If you look at the Apogee site they have a response curb.

 

[CJO]

So are the PAR meters reading more PAR from the blue spectrums then they should?

When I cranked on the 24 CWs they blue almost 400W of PCs out of the water.

The opposite. The Apogee meters read about 10-20% lower PAR on the blues than they actually put out.

CJ

 

[TheFishMan65]

Here is a link to the response curve (do I have the right one?). I purchased just a sensor so I think at 450 is about 65%. So if I have a reading of 150 it should really correlate to about 150 / 65% or 230 PAR. For CW (XR-E) the range from 500-600 is about correct, but they have a large peak at 450. Anyone know how to read percenatage output of frquence from that chart? If I go by area under the curve maybe 1/4 is 450. So 25% of 1/.65 is .38 so I think a reading of 150 would be 150 * 1.38 or 207. So if I reading of 300 was split 50/50 then it is really 437.

Tonight I will try and read RB and CW separately. But can anyone tell me if the math is correct?

Thanks

 

[bamf25]

I really think led's are going to require us to ajust our thinking on how we measure light output.

 

[TheFishMan65]

I agree, I am not sure how yet. That is why I was hoping to get some comments on how to adjust PAR numbers.

 

[terahz]

PAR calculation look right to me. I was doing + 20% before by guessing but looks like I'll have to do +30% now on my 50:50 setup.

I guess the +% will be a bit more complex based on the ratio, current and type of LEDs used. Also, there are two PAR sensors by apogee that are calibrated approx 10% apart so these need to be taken into account as well, I guess.

 

[bamf25]

I agree, I am not sure how yet. That is why I was hoping to get some comments on how to adjust PAR numbers.

I have just seen too many people ordering massive numbers of LED's then saying they are only running them at 500 mA or dimming them way down because they were bleaching their corals. Says to me that we are all still learning and experimenting with LED's, and in general they are more powerful than we expect. With that said, I believe they are the future of the hobby, especially with how energy prices are just going up. We have only been playing with them for 2 to 3 years, and we are still learning. The other "problem" with LED is the benchmarks keep moving as the tech gets better. What worked for led's 3 years ago does not apply now. The XM-L's at 3000 mA will give like 1000 lumins for 3.3 w roughly, that is insane when you think about it.