Anyone Thinking of Dumping LEDS and going back to Halides

[theatrus]

It has been 6+ years with LED and we only still have the same promises as back on 2009-2010. It always "needs more time," "better understanding by the user," "better blend of colors," "too intense," or whatever have you. Not much has changed over the years. When is enough enough? T5 never took that long to get good.

Mass adoption of LED lighting pushing high efficiencies and better spectral mixes? There are a huge number of lighting products available now which didn't exist 6 years ago.

He is what I do not understand... say that you PWM a LED... does the sine wave drop off to zero when the PWM kicks in? Does the wave look digital if we had good equipment to analyze it? I know that all electricity has cycles, but the plasma/gas in a tube or MH bulb continues to burn which should keep the sine wave very steady.

Its somewhat complicated by the exact setup, but without any output capacitors (common for high frequency PWM), the intensity does drop to 0 within microseconds (parasitic capacitance and wire inductance control this). Using any rolling shutter (phone) camera will let you get a wag on the frequency by the banding lines marching across the screen

A camera with a high framerate (say 240fps+) can capture an approximation of the flashes from a magnetic ballast HID lamp; it would look like a strobe light. Higher frequency electronic ballasts would not be visible as gas lamps don't drop to 0 output as fast as a diode would.

Its quite possible to provide dimming by adjusting the actual current limit of the switch mode cycles (usually +/-20% peak to peak, and run at a biologically improbably frequency), but I doubt as many people bother. The commercial fixtures don't generally advertise what they do, and I don't own any to tear down to see what their control scheme is.

 

[karimwassef]

jda- I'm not sure I understand the question.

Photons operate at a very high frequency compared to any PWM (THz vs KHz)... There's no comparison of sine waves here. The power source to an LED is a constant current DC source. That's pulsed on and off so the average power is reduced. Yes- when it's off, it's off. The period of "on" or "off" looks very very long to a photon source.

To us or to corals, they just look dim because biological receptors operate at an even slower rate. And the biological impact is the same. If you touch a 1000F piece of wood for one microsecond, do you burst into flames? No... Because the energy transferred is limited by the physics of the transmission and the duration of exposure...

 

[jda]

My point is quite simple... I don't think that anybody fully understands what a diatom is sensitive to, or not. Some of the better LED tanks that I have seen run at 100% with no PWM, so I have always thought that the assumption that the coral cannot "see" the strobe effect is probably a bad one. No real data, just observation and supposition.

How does anybody know what looks dim to a coral? ...or the organisms in a coral? I only see that some coral suffers greatly under LED and there has to be a reason, and nobody knows why which is proof enough that they are not fully understood.

 

[karimwassef]

I agree with gathering data and I run at 100% too. I only use PWM to transition on and off slowly. If I want to actually dim, I turn a set off.

Without data, I wouldn't side with pulsing light being negative though. If I were to consider a theory, it would be that biological tissue (from a dinoflagellate or my eyes) have response times that are more comparable than different?

 

[oreo57]

I know you're trying not to sound like a know it all, but laughing at people isn't exactly supportive of different ideas.

I know I shouldn't do this but the setup is JUST too good?
How is the above any worse than this:

typical MH user won't switch because they generally have more experience, know what they are looking at and have yet to ever see a tank under LED that would not look better under MH.

sorry just find that "special"....

Some of the better LED tanks that I have seen run at 100% with no PWM,

nothing to do w/ the fact that PWM "dims" the lights huh...

anyways, trace of an LDD output to the diode at 100%..(PWM not "enabled")

No PWM, IN: 24v, 756mA; OUT: 16.53V RMS, 970mA;Power IN: 18.144W Power OUT: 16.035 Efficiency: 88.37%

PWM "enabled" at 99%

99% via PWM, IN: 24v, 762mA; OUT: 16.44V RMS, 957mA;Power IN: 18.288W Power OUT: 15.733W Efficiency: 86.02%

http://www.ultimatereef.net/forums/showthread.php?691102-Mean-Well-LDD-H-vs-XPPOWER-LDU56/page2

I don't "buy" that waves of photons (even ignoring "out of phase" reflections ect ) effect single cell organisms that much. I do reserve the right to be proven wrong though. Stranger things have happened.
Not being wrong, that happens plenty..
http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/White-Papers/Flicker.pdf

all artificial light sources flicker

 

[lpsouth1978]

Here is a pic of the tank as it sits today. The MH are on the right side. The rest of the tank is still lit by the LED's.

 

[oreo57]

Here is a pic of the tank as it sits today. The MH are on the right side. The rest of the tank is still lit by the LED's.

Still haven't included est. of watt output on each side...

 

[lpsouth1978]

Still haven't included est. of watt output on each side...

Far right 1/3rd of tank (MH) is 500W. Each of the other 2/3rds (LED's) is 366W.

 

[ReefInterest]

For me, the jury is still out on the reef side of LEDs. However, I recently moved the contents of a 40 breeder planted tank (17" high) with 192 watts of PC lighting (Coralife) to a 26 bowfront (21" high) with only 32 watts of LED lighting (Marineland). The plants were pearling right away. The fixture was around $50 shipped on Ebay. I should save around $70 worth of electricity per year.

For planted tanks, I think we are there. No need for anything else but LEDs. Period, end of story.

The 40 gallon breeder was recommissioned as a reef with two Fluval Sea LEDs (v1) at around 64 watts total (the fixtures cost $75 each on Ebay). We'll see how well they do when I begin introducing coral. Interestingly, they aren't high wattage, have surface mounted LEDs and have a wide dispersal, and claim to have a "good" spectrum for corals. We'll see...

 

[USC-fan]

Here is a pic of the tank as it sits today. The MH are on the right side. The rest of the tank is still lit by the LED's.

Why does the LED side look so much better? Is it just the photo or you running a very white bulb?

Far right 1/3rd of tank (MH) is 500W. Each of the other 2/3rds (LED's) is 366W.

WOW 500 watts. So you have 2x MH 250 on the right? It only looks like its lighting 1/4 of the tank.

 

[karimwassef]

Why does the LED side look so much better? Is it just the photo or you running a very white bulb?

Wow. talk about perception.. beauty is in the eye of the beholder.

I was about to ask why the MH side looks so much brighter and nicer...

 

[USC-fan]

Wow. talk about perception.. beauty is in the eye of the beholder.

I was about to ask why the MH side looks so much brighter and nicer...

Its looks washed out. Look at the rock. They dont even look purple but grey. Looks like a 10k bulb.

It might just be the photo.

 

[karimwassef]

That's what sunlight looks sparkling over living reefs. I don't think it's washed out.

The ones on the left look overcast and "cartoonish" to me.

It's not a criticism.. it's a reflection of expectations of beauty. It's just my eyes and brain are looking for different cues for beauty.

There's no right answer... just what you like

 

[lpsouth1978]

Why does the LED side look so much better? Is it just the photo or you running a very white bulb?

WOW 500 watts. So you have 2x MH 250 on the right? It only looks like its lighting 1/4 of the tank.

Its looks washed out. Look at the rock. They dont even look purple but grey. Looks like a 10k bulb.

It might just be the photo.

It is the photo that makes it look like that. The MH are 14k Phoenix bulbs. Having the different light sources makes it difficult to accurately show the colors. The MH are mounted front to back and are only lighting 1/4 to 1/3 of the tank. having a tank that is 36" deep requires more bulbs. If we switch to MH, we will have 6-8 bulbs over the tank.

 

[lpsouth1978]

Also, the rocks are not purple. There is still very little coraline growth on them. The rocks under the MH are actually what the rocks look like. The LED's make them look purple in the picture.

 

[USC-fan]

It is the photo that makes it look like that. The MH are 14k Phoenix bulbs. Having the different light sources makes it difficult to accurately show the colors. The MH are mounted front to back and are only lighting 1/4 to 1/3 of the tank. having a tank that is 36" deep requires more bulbs. If we switch to MH, we will have 6-8 bulbs over the tank.

Oh okay. Those are my favorite bulbs!! Im debating led vs those de bulbs myself. But i will be running t5s with either.

I see why you went led. That a lot of heat and power. If i get the reflector i want it will only take a single mh to light my current tank.

Just very hard to over look the led advantages.

 

[oreo57]

Far right 1/3rd of tank (MH) is 500W. Each of the other 2/3rds (LED's) is 366W.

Just for a bit of clarity..
If you divide the tank in thirds you have, roughly 183w led, 183w led, 500w mh ?????

and the color ratio of the led's???

 

[lpsouth1978]

Just for a bit of clarity..
If you divide the tank in thirds you have, roughly 183w led, 183w led, 500w mh ?????

and the color ratio of the led's???

The math I used is as follows (and is a rough estimation):

456 (total number of LED's)/3 =152 per 1/3rd
152 - 30 (number of led's not working in each 1/3rd) = 122
122*3watts = 366 watts per 1/3rd or 366w led, 366w led, 500w mh.

Hope this helps.

 

[lpsouth1978]

Sorry, the color ratio is:

32 royal blue (originally 62, but 30 are not working in each 1/3rd)
30 Neutral white
18 Green
12 red
18 blue
12 uv

This is per 1/3rd of the tank.

 

[oreo57]

The math I used is as follows (and is a rough estimation):

456 (total number of LED's)/3 =152 per 1/3rd
152 - 30 (number of led's not working in each 1/3rd) = 122
122*3watts = 366 watts per 1/3rd or 366w led, 366w led, 500w mh.

Hope this helps.

Yep much appreciated.. BTW: I've found this a fairly useful tool for a number of things.. Mostly rough estimates;Worked up a guesstimate of the 2 spectrums. Ignored R and G since you barely added anything and the ratio of white to blue was 1:1 Purple was 1/10. (100/100/20)
charts show est. mH's ect..

http://spectra.1023world.net/

Play w/ it a bit w/ your own numbers..

Oddly the W ratio between the 2 is about the same... Well yours is .73 Mine .82. (never mind, that is by area I believe)
Used 2 250W 14000k Ushio MH..
Couldn't tell what blues you used so just used CREE RB for the led's. And CREE neutral white..Semi LED 390-40o (opps, probably should shift that to 400-410..shifts the purple to the right and makes it better..score of 73)