Blame it on the lights.

[SB Reef Lights]

The other issue is people often blame a complete category of lighting as opposed to individual bulbs or models. For example I had no luck with LEDs but switched to metal halide and everything is better. Perhaps you had the wrong LEDs. Or poor placement of your corals and they like the single point better.

There's also a lot to be said about single point lighting vs array or broadcast lighting. One of the big advantages of t5's is with their larger fixture and quality reflectors they tend to get more light underneath the sides of corals than a typical single point or even LED. However it's very easy with LEDs to use supplemental bars on the outside edge is shining in to create the same effect while still saving money on electricity, rebulbing and adding the ability to dim your lights based on your corals needs.

The size and depth of your tank makes a large difference as well. You would have to have an incredible number of T5 bulbs in order to penetrate properly to the bottom of a 32 or 36 inch deep tank. At the same time if you run metal halide strong enough you end up cooking the top corals. Running a large array of LEDs will allow you the penetration without having the drawback of a single point where PAR is incredibly high directly under the light source.

 

[atoll]

^^^ Well put and more food for thought. ^^^

 

[ou12004]

You have a really nice tank, but looking at your FTS it looks like some of your SPS are STN's from the bottom up, but it is hard to tell without being able to zoom in. I had good growth with just LED's and would not suggest that others can't have an awesome tank with just LED's, as your tank is an example of. But my LED's did not provide good enough coverage under the SPS colonies alone, so I am blaming the LED's.

Blame mine for the colour growth and basing out then

 

[erk]

I believe LEDs as well as all lights can be the reason for lack of growth or bad colors in certain tanks. I think LEDs are more likely to cause these issues due to the point source and high customizability with wavelength and intensity. So many factors to handle at once, it is very easy to get it wrong. Experimenting with LEDs on an old growth tank can lead to large die off and I don't think I'd be willing risk large colonies dying just to switch to a new light. Corals attain certain shapes and growth patterns to match their environment. Going from T5s to LEDs can cause die off and browning out if the coral growth doesn't allow it to take advantage of the light.

 

[atoll]

You have a really nice tank, but looking at your FTS it looks like some of your SPS are STN's from the bottom up, but it is hard to tell without being able to zoom in. I had good growth with just LED's and would not suggest that others can't have an awesome tank with just LED's, as your tank is an example of. But my LED's did not provide good enough coverage under the SPS colonies alone, so I am blaming the LED's.

No STN on my corals you are mistaken. However one small frag didn't make it in the move from tank to tank all the others are doing fine and healthy from what I can see. You can see more close ups of my corals in my build thread. You will see a few corals and frags that were damaged when I got them (cheap of course) but all are coming back nicely.

 

[atoll]

I believe LEDs as well as all lights can be the reason for lack of growth or bad colors in certain tanks. I think LEDs are more likely to cause these issues due to the point source and high customizability with wavelength and intensity. So many factors to handle at once, it is very easy to get it wrong. Experimenting with LEDs on an old growth tank can lead to large die off and I don't think I'd be willing risk large colonies dying just to switch to a new light. Corals attain certain shapes and growth patterns to match their environment. Going from T5s to LEDs can cause die off and browning out if the coral growth doesn't allow it to take advantage of the light.

Hence why many LED lights now have an acclimatisation programme built in I guess. However, all my frags come from colonies grown under LED's I haven't got a single LFS using T5s or HQI on their coral selling tanks.

 

[Sabellafella]

To be honest i think the whole road that follows down to the "led" growth/color issue has to do with tinkering too much. Ive said this in other threads before, ive bleached corals moving them 2 inches down with t5s before. With the addition of an extra 10-20 par makes a big big difference with coral health the good and the bad(this can be done with upping led intensity mearly 2%). Anyone can disagree, but people who keep changing their light settings/acclimation mode/colors/intensity will never give the chance to if not all your corals to adapt to its normal daily conditions. An increase from 40-50 % one month can be devastating. Even for the people who keep their leds on the same setting for months on end, to only windup not liking the results. Then the switch back to something else. Organisms react differently to different lighting, you need to stick with the same spectrum, same intensity, same routine every single day or else youll never give organisms a chance to grow properly

 

[erk]

Hence why many LED lights now have an acclimatisation programme built in I guess. However, all my frags come from colonies grown under LED's I haven't got a single LFS using T5s or HQI on their coral selling tanks.

All my LFSs seem to be transitioning to LED over their frag tanks. It's very helpful when acclimating them to my tank. My experience though is that no single light type is perfect. Corals need both diffuse and point light as that mimics their natural environment. Then keep that light constant. I bought a par sensor because I got tired of guessing with my custom LEDs. Expensive, but worth it. I'd rather not guess/experiment when setting up lights over my tank.

 

[SB Reef Lights]

Most PAR sensors are inaccurate when dealing with leds, or even t5 bulbs Wyeth a lot of low wavelength blue and purple. For example the apogee drops on sensitivity quickly below 470nm.

Of course PUR as a percent of PAR is the more important number to focus on. For example I can make an led with all green diodes. It will have high PAR yet grow nothing.

LED design is more than just which wavelengths you pick, though that is important. Optics play a big part as well as array verse single point. And number and placement of units. For example my display tank is 42" front to back and 32" deep. No single fixture would cover it and a single point would have too much shadowing. By using more smaller units, spread out I get more consistent PAR across the tank with almost no shadowing. I also use a mix of 90* and 120* Optics for penetration on some diodes like 450nm, and better color blend on diodes like 420nm, red and green.