Do people struggle with LED more because of the customizability?

[ktownhero]

Originally Posted by d2mini

Yes, part of the problem is giving the user ultimate control.
The other problem that has nothing to do with the user is the terrible coverage and the associated pinpoint light source. You can see it in the graphs on the manufacturer's websites. Intense, high par directly under the bulb/puck and then a dramatic drop as you go out from there. I think all manufacturer suggestions of how many lamps are needed is about half of the reality. At least.

I think companies like Lani that are attempting to provide full coverage over the tank are moving in the correct direction.

Some manufacturers are starting to use reflectors, right? That, I would imagine, would help some other issues you're describing.

[gbru316]

Originally Posted by ktownhero

Some manufacturers are starting to use reflectors, right? That, I would imagine, would help some other issues you're describing.

LEDs are a directional light source. Reflectors "reflect" light and point it in the desired direction. Since LEDs are already pointed in the desired direction, this wouldn't do much unless they were purposely directed away from the tank and the light bounced back into it.

People usually control the spread of LEDs with lenses.

[ktownhero]

Originally Posted by gbru316

LEDs are a directional light source. Reflectors "reflect" light and point it in the desired direction. Since LEDs are already pointed in the desired direction, this wouldn't do much unless they were purposely directed away from the tank and the light bounced back into it.

People usually control the spread of LEDs with lenses.

Right, but reflectors can still be used and I know at least one of the high end LEDs use them... The GHL Mitras maybe? Reflectors do more than point light. Namely, in the case of LEDs, they can help with light spread.

Edit: yup, the ghl mitras

Special coated high-performance LED-reflectors carry the light also into the depth, no useless divergence losses of the light to the sides.

http://ghlna.com/mitras-lx-6200-pendant/

[gbru316]

I should rephrase: there is no light to be reflected with LEDs because 100% of the light emits from one side of the chip. It'd be like putting a mirror behind a flashlight. Unless the reflectors are beside or in front of the emitter, they're useless. If they are beside, they do the same thing as lenses. That is, they focus the light.

Now what reflectors CAN do is reflect the light that gets reflected from the top of the water back into the tank, making the LED a bit more efficient. This benefit, though, would be so marginal that it may not be readily visible. (Or it may, I've never tried it and I don't feel like doing math at the moment).

[d2mini]

Originally Posted by ktownhero

Right, but reflectors can still be used and I know at least one of the high end LEDs use them... The GHL Mitras maybe? Reflectors do more than point light. Namely, in the case of LEDs, they can help with light spread.

Edit: yup, the ghl mitras

Special coated high-performance LED-reflectors carry the light also into the depth, no useless divergence losses of the light to the sides.

http://ghlna.com/mitras-lx-6200-pendant/

Whatever they are talking about is not going to act anything like a mh bulb in a big metal reflector.

[gbru316]

So the mitras are using reflectors instead of lenses. It accomplishes the same thing.

[dartier]

Originally Posted by d2mini

I think companies like Lani that are attempting to provide full coverage over the tank are moving in the correct direction.

For my DIY fixture, built before I had any idea of what was good, I used a big array of 10W multichips (20 chips), that are used without lenses, with lots of distance between each 10W chip covering the whole water surface.

In later upgrades I added 3W LEDs (Rebels) with 60 degree optics in between the 10W LEDs to penetrate to the bottom.

I have never used T5's, but I suspect that the tendency to add T5's to LEDs accomplishes what my 10W LEDs without lenses do (for me).

Too early to say if it is the way to go (for me), but so far I am pleased with the way it has worked out.

Dennis

[gbru316]

I've noticed a lot of people, when building an LED array, tend to choose optics based on the coverage on the bottom of the tank (if they do the trigonometry at all).

IMO, this is the wrong method. You end up with spotlighting, "disco," and uneven vertical coverage. A properly designed array will feature coverage based on the surface of the water so that it will be relatively even as it penetrates the tank.

[ktownhero]

Originally Posted by gbru316

So the mitras are using reflectors instead of lenses. It accomplishes the same thing.

Not necessarily. There is light wasted with a lens because it can only focus what is already going to hit it. A reflector can capture light spillage, which does exist with LEDs just not behind them. A reflector should be able to more efficiently use the energy and I would imagine can reduce the "single point source" effect of LEDs which is often the cause of shadowing problems.

[AdamNC]

Would having the 120 degree lenses work better then 90 degree lenses even in small tanks like mine? Even though I have 3 pucks in a 30 inch tank, I still feel like it's not full coverage for my sps. The bottoms of the coral "sticks" don't seem to get any light whatsoever. Soft, LPS and Zoas I have no worries about with the 90 degree lenses.

[gbru316]

Depends. With a wider distribution, the lights won't penetrate as deep. How high above the water is your fixture?

[Hotwired]

I think it is like most things. The more control the user has the higher chance of experimentation which comes with failure

[Big E]

Originally Posted by ktownhero

A lot of people seem to have trouble using LEDs and there are probably a variety of reasons. But I also noticed that due to how easily LEDs can be customized (color and intensity), people often have incredibly complex ramping profiles to the point where it may take up to a solid 50% of their total lights-on time. But not only in overall intensity but in adjusting individual color profiles almost continuously throughout the day.

Do you think that part of the reason we see issues with LEDs is due to the fact that these complex ramps are used on a day-to-day basis? Whereas with other lights you often just have more of an on-off scenario during which time your color and intensity remains consistent.

I believe this is an issue that is seldom talked about.......certain pigments will only excite, fluoresce, ect. under specific conditions. If a coral is not getting the correct spectrum for enough hours per day it's not going to thrive.

If you have the ability to set a good spectrum profile and ramp the LEDs up and down without changing the spectrum through out the day it's going to make a big difference.

I'm not aware of what the software is capable of now on new units but if you can change intensity without changing spectrum it's going to cause a lot less problems and lead to more success.

Of course this is only one variable.............as mentioned coverage,reducing hot spots, spectrum capabilities of the actual unit, and diode configurations all come into play.

[Wazzel]

There is no reason to ramp the spectrums up and down during the day. Tube and MH work just fine with a set spectrum and on/off approach.

LED systems get way over thought.

[gbru316]

Originally Posted by Wazzel

There is no reason to ramp the spectrums up and down during the day. Tube and MH work just fine with a set spectrum and on/off approach.

LED systems get way over thought.

Who said it was a necessity?

Many people start their actinics prior to their daylights, which produces a stepped transition from dark to light. Ramping just furthers that concept.

I've often seen fish "freak out" when lighting goes from full off to full on. It's unnatural. The allure of a reef tank is having a bit of nature in our house, so why not replicate it to the best of our ability?

[joejvj]

I agree with Wazzel. In the old days (not that long ago) I used MH and Power Compacts with walmart $6 on/off timers and all my SPS/LPS thrived and grew. Now that I switched to LEDs, I see no difference in growth or health using sunrise/sunset ramps.

[gbru316]

Ramping isn't done to improve coral growth or color.

[joejvj]

Originally Posted by gbru316

Ramping isn't done to improve coral growth or color.

I thought anything/everything we add to our aquariums is to improve the health of our livestock.

[Mark426]

Originally Posted by d2mini

Whatever they are talking about is not going to act anything like a mh bulb in a big metal reflector.

I think it may be just semantics, the description is so vague, GHL reflectors = lenses. From what I can see that's exactly what they are...lenses.

[gbru316]

Originally Posted by joejvj

I thought anything/everything we add to our aquariums is to improve the health of our livestock.

Nope. There is a fair amount of stuff we do just to please ourselves that has little or no impact on coral.

[AdamNC]

Originally Posted by gbru316

Depends. With a wider distribution, the lights won't penetrate as deep. How high above the water is your fixture?

Standard height of the legs, I think 8 inches and the tank is 18 inches tall with a 2 inch sand bed.

[AdamNC]

Originally Posted by joejvj

I agree with Wazzel. In the old days (not that long ago) I used MH and Power Compacts with walmart $6 on/off timers and all my SPS/LPS thrived and grew. Now that I switched to LEDs, I see no difference in growth or health using sunrise/sunset ramps.

I bet your electric bill has gone down though.

[ca1ore]

Originally Posted by ktownhero

A lot of people seem to have trouble using LEDs and there are probably a variety of reasons.

There do seem to be people who swear by LED and have successful tanks as evidence; and then there are the 'switching back to MH' folks. How does one reconcile this? My own opinion is essentially as you imply, that there are simply too many combinations and permutations to be able to draw any useful conclusions about success or failure - whether its intensity, spectrum choices, etc.

[Wazzel]

Originally Posted by ca1ore

There do seem to be people who swear by LED and have successful tanks as evidence; and then there are the 'switching back to MH' folks. How does one reconcile this?

My opinion is if it works for some and not for others it is not a hardware issue.

[d2mini]

Originally Posted by Wazzel

My opinion is if it works for some and not for others it is not a hardware issue.

You also have to realize that "works" means different things to different people. And the particular coral that one person has in their tank are not the same corals that another person has in their tank.
I've seen plenty of posts where someone says that their tank is doing great under LED and then they post a pic.
Of course I've seen the opposite too, but the point is "doing great" doesn't mean anything.