Hi Salty! Always good to talk with you!!
I will put here my point of view.
The curious trend I see now is to add t5 to Lights that already are proven to grow corals.
The point is that LEDs are also proven to grow corals by now.
There are many LED only tanks with corals growing and not dying. Good colors too. We all see that.
So LEDs are proven to grow corals. I think is time for us to stop using such expression.
And those T12s and T8s back in the day would also grow corals.
The most common mistake I see(one of them) is that the primary Light , led in this case, is the top of the tank is getting 600-800 par from the primary and then. Adding some t5 that only add about 200 par to the top of the tank. By the time that gets to the bottom it’s 25 par or less.
IMHO there are 2 groups thinking differently now in regards to "primary light source".
One group thinks that the primary light source comes from the quality of light offered for growth and color.
The other group sees it as the PAR number coming for either light sources, as a comparison.
Many would consider T5s above the LEDs in terms of keeping the health and growth/colors of the corals because of the uniformity, spectrum blend and ability of reflection with multiple slots. Therefore, the more T5s over a shallow system (max.24") the healthier those corals would grow.
I had a thread just recently where the it was the same supplemental question but the light was a 250 mh. That’s like a candle in the sun.
The second mistake is see in supplemental is ,kessil aside , most use these wacky color schedules in the led when the led at its 100% native spectrum ratio is designed to grow corals.
The candle in the sun that you are talking about could be compared in a better fashion to the "spot light" (sun) and the "sky light".
The spectrum of each source blends with the shimmers and offer optimum light. When we use the T5s, as "sky light", it will really embrace the tank and the reflectors will give the punch to cover shadows in a more efficient way than LEDs, which are like beams (little spot lights). There is a big difference of light spread between LEDs and T5s.
Shadowing fwiw , is not anything to do with spectrum or Light source.
I disagree with that one. The light source has a huge influence in shadowing. Metal halides and T5s are offering the most ability for reflection when using the proper system for the aquarium. LEDs by nature, as a beam of light using only lenses, lose to the halides, as the other spot light type of light source. The reflection from from a good MH/T5 reflectors will distribute the light and re-reflect that light through the whole system in a much more efficient way than the LEDs. That is why so many people are beginning to see huge differences after adding T5s to their LEDs, changing all for T5s, or changing the whole system for MH/T5s.
There are other really important differences like the UV from the halides and the relatively constant spectrum offered from the halides. The LEDs aren't able to compete with that either. Not bashing, just exposing the facts, like Mr. Julio Del Aquila would.
It’s the physics of where the subject is under the light. The light is directly overhead to the Coral.si most of the front of the coral is dark. So adding a supplement slightly forward of the primary will light more of the face of the coral.
In photography we call that fill Light.
Well, the nature of LED will again prohibit such efficiency in reflection because the lens can't compete with good MH/T5 reflectors.
If you have an opportunity to talk to Dr. Sanjay Joshi he will explain that to you. He has that happening in his 500gal with the Radions and didn't happen as much with the halides. And he has lots of Radions as you may know...
In nature the reflection of light is very similar to a halides/T5s combo.
T5 and large MH reflectors there are rarely these problems becuse of this simple fact. It’s a large overhead source already and provides its own fill.
You got it, man!
So if you have a row of say ap700 down the middle of the tank , depending on the aqua scape , yes you may have shadowing down the front of the rock.
If the ap is set to 100% , you add a t5 or two it probaly wont add much par spectrum wise , but maybe a taste of fill to the front. If you add an led strip in the same place , it’ll do more becuse most strips have the out put of 2-4 t5’s.
That s why people see the difference of removing the LEDs and filling that precious space with the t5s to supply the PAR needs as a whole. If you have the LEDs and T5s you are simply allowing your visual taste to the satisfaction, not providing a uniform light (PAR and spectrum) to those corals. Some areas will get the LEDs and some other areas will have a tiny amount of the T5 supplementation. Those areas will still suffer because there isn't enough supply. When you add all T5s each individual reflector from each bulb will add to the punch and fill in with amazing uniformity. That should be the proper way to use T5 systems.
The number of bulbs, reflectors, bulb cooling for efficiency, bulb spectrum choices, and distance from water surface are IMHO very important and qualities of the T5 as a light source. All that will play with efficiency.
It’s these reasons I don’t prefer small emitter lamps over a tank.
If I did use kessil , I’d use 6-8 160s rather than two ap700 over somthing like a 180 gal tank.
Most LEDs in US should be considered "small emitter" over the tanks.
The pucks are a joke IMHO, with all the respect. And people still consider them as the "best lights available" just because of stores and PDF publication. Not to make anyone upset. Just facts.
Unless we have something like the LANI or a Phillips Coral Care that are considered the very best among most of the LED lovers. Those fixtures are better. They resemble the wonderful T5s.
This is the way I see. I believe many people are starting to understand the points and that's why more and more are finally coming to realize the amazing difference when they decide to change their LED for metal halides, T5s or both. There is an actual difference because of reflection and uniformity. Corals will respond and grow very similar to how they do in the ocean.
Again, I'm just trying to give my opinion here.
We all try to understand why things happen.
Would be so great to have people posting here their actual observations in coral growth and health comparing the 3 light sources.
The description and pictures of their results would tell us much more than this or any other post!!
Aloha.
