How many LEDs on a frag tank

acabgd · 06/28/2012, 02:33 PM

This is an existing 75x20x12 frag tank (water level is actually about 10"). Does anyone have an estimate on how many hybrid LEDs would be needed to light this for SPS corals?

We are thinking about using these LEDs: http://www.ebay.com/itm/EPISTAR-20W-...item33740eb3ae

Thanks a lot!

firebirdude · 06/28/2012, 08:29 PM

Tough to say with those LEDs. Output is not going to be the problem with a tank of that depth, it's coverage. Which, honestly, makes it pretty pointless to use a multi-chip LED like that. Stick with the common single emitter 3W LEDs. I'd say two 48 LED kits would be great.

JoshuAcOOk · 06/28/2012, 09:20 PM

u could always use a lens to focus the light.
im not sure if the white kelvin reading is the right number though. its 20500, and cool white is 5-6000

try this one
http://www.ebay.com/itm/1pc-10W-Acti...ht_2909wt_1219

firebirdude · 06/28/2012, 09:28 PM

[QUOTE=JoshuAcOOk;20411579]u could always use a lens to focus the light.
im not sure if the white kelvin reading is the right number though. its 20500, and cool white is 5-6000/QUOTE]

Uhh a lens would make the situation worse bro...

acabgd · 06/29/2012, 04:52 AM

Thanks everyone for your replies. The idea to use these leds came from this thread: http://www.reefcentral.com/forums/sh....php?t=2128756

Obviously we wouldn't go with 100W leds as so much power should not be needed for such a shallow tank. The question was whether we could generate enough light using let's say 10 20W leds spread over the tank.

firebirdude · 06/29/2012, 07:32 AM

I don't have any personal experience with the LEDs higher than 3W. But honestly, this is all about color mixing while maintaining coverage. At the same time, the entire lighting spectrum needs supplementation. Coral photosynthesis is, indeed, favored by the blue wavelengths, but it's not the only show in town. We already have plenty of individuals with several years of Cool White/Royal Blue use experience who were not happy with their coral colors (Me for one...), then saw noticeable improvements switching some cool whites for a more neutral white and adding some colored LEDs. Big name manufacturers are starting to swing this way as well. So again, power has never been the problem. It's area coverage and blending between emitters.

Everyone's opinion will likely be different, as this is all still very new in our industry. But I built my first LED fixture in early 2009. I've watched how softies, LPS and SPS react over a period of years. My honest opinion as to the ideal fixture would be a crap ton of multi-colored 1W LEDs. Not a big deal on nano tanks, but would be pretty cumbersome on a tank of your size. Something like 80 Royal Blues, 35 Cool Whites, 35 Neutral Whites, 10 True Blue, 10 violet, 10 red, 10 green. Sounds crazy, but this wouldn't be hard for a manufacturer. This many LEDs would allow them to be close together and blend well, and still have the sheer numbers for coverage. Being 1W will keep costs within reason and make heat dissipation easier. Again, it's not about power. We've always had plenty of that (90+% of CREE users don't even run full power).

acabgd · 06/29/2012, 10:04 AM

Thank you very much for a detailed and comprehensive reply. This is exactly the kind of info I was looking for!

06/28/2012, 02:33 PM	#1
acabgd Registered Member Join Date: Jan 2012 Location: Belgrade Posts: 1,086	How many LEDs on a frag tank This is an existing 75x20x12 frag tank (water level is actually about 10"). Does anyone have an estimate on how many hybrid LEDs would be needed to light this for SPS corals? We are thinking about using these LEDs: http://www.ebay.com/itm/EPISTAR-20W-...item33740eb3ae Thanks a lot!

06/28/2012, 09:20 PM	#3
JoshuAcOOk Registered Member Join Date: Jun 2011 Posts: 118	u could always use a lens to focus the light. im not sure if the white kelvin reading is the right number though. its 20500, and cool white is 5-6000 try this one http://www.ebay.com/itm/1pc-10W-Acti...ht_2909wt_1219 Last edited by JoshuAcOOk; 06/28/2012 at 09:39 PM.

06/28/2012, 08:29 PM	#2
firebirdude User and Abuser Join Date: Aug 2008 Location: Oklahoma Posts: 1,836	Tough to say with those LEDs. Output is not going to be the problem with a tank of that depth, it's coverage. Which, honestly, makes it pretty pointless to use a multi-chip LED like that. Stick with the common single emitter 3W LEDs. I'd say two 48 LED kits would be great.

06/28/2012, 09:28 PM	#4
firebirdude User and Abuser Join Date: Aug 2008 Location: Oklahoma Posts: 1,836	[QUOTE=JoshuAcOOk;20411579]u could always use a lens to focus the light. im not sure if the white kelvin reading is the right number though. its 20500, and cool white is 5-6000/QUOTE] Uhh a lens would make the situation worse bro...

06/29/2012, 04:52 AM	#5
acabgd Registered Member Join Date: Jan 2012 Location: Belgrade Posts: 1,086	Thanks everyone for your replies. The idea to use these leds came from this thread: http://www.reefcentral.com/forums/sh....php?t=2128756 Obviously we wouldn't go with 100W leds as so much power should not be needed for such a shallow tank. The question was whether we could generate enough light using let's say 10 20W leds spread over the tank.

06/29/2012, 07:32 AM	#6
firebirdude User and Abuser Join Date: Aug 2008 Location: Oklahoma Posts: 1,836	I don't have any personal experience with the LEDs higher than 3W. But honestly, this is all about color mixing while maintaining coverage. At the same time, the entire lighting spectrum needs supplementation. Coral photosynthesis is, indeed, favored by the blue wavelengths, but it's not the only show in town. We already have plenty of individuals with several years of Cool White/Royal Blue use experience who were not happy with their coral colors (Me for one...), then saw noticeable improvements switching some cool whites for a more neutral white and adding some colored LEDs. Big name manufacturers are starting to swing this way as well. So again, power has never been the problem. It's area coverage and blending between emitters. Everyone's opinion will likely be different, as this is all still very new in our industry. But I built my first LED fixture in early 2009. I've watched how softies, LPS and SPS react over a period of years. My honest opinion as to the ideal fixture would be a crap ton of multi-colored 1W LEDs. Not a big deal on nano tanks, but would be pretty cumbersome on a tank of your size. Something like 80 Royal Blues, 35 Cool Whites, 35 Neutral Whites, 10 True Blue, 10 violet, 10 red, 10 green. Sounds crazy, but this wouldn't be hard for a manufacturer. This many LEDs would allow them to be close together and blend well, and still have the sheer numbers for coverage. Being 1W will keep costs within reason and make heat dissipation easier. Again, it's not about power. We've always had plenty of that (90+% of CREE users don't even run full power).

06/29/2012, 10:04 AM	#7
acabgd Registered Member Join Date: Jan 2012 Location: Belgrade Posts: 1,086	Thank you very much for a detailed and comprehensive reply. This is exactly the kind of info I was looking for!