Why do people run 6500K bulbs?

[Anirban]

I used to run a Tropic 6500K in my two bulb T5 setup to complement my hydra. Its more of a daylight spectrum and my corals including SPS were doing great in terms of growth and colours. I recently changed that with a ATI coral plus 2 weeks back just for experimenting. Nothing drastic yet but will know in few months.

 

[saltyfilmfolks]

Maybe softies. It was always 10 and 20k MH.
I tried par 38 from home depot nothing looks good or last under them. I don't see how a led would do any better from home depot beside burn your corals. The beams are too narrow and focused.

But if you're talking about 6500k with other bulbs like 10k i could see it working.

Oh and on softies , actually a lot of the spectrum needs of generalist coral zooox are Not exclusive to hard or soft coral as it turns out.
Same with intensity needs.
Trip right ?

 

[saltyfilmfolks]

T5's took over and i can't lie they do well with the right unit and reflectors. MH are still awesome but i can understand why they would think they're scary lol.
I was 16 when i got into the hobby and MH looked dangerous then.

Oh the kids and the blue thing. Oy!

It's the spectrum myths really.
You should check out the debates on a 12k Phoenix.

Yea blue an a touch of red, but your clown is now brown.

 

[Sycoticrealm]

Oh and on softies , actually a lot of the spectrum needs of generalist coral zooox are Not exclusive to hard or soft coral as it turns out.
Same with intensity needs.
Trip right ?

You guys are talking about running it with other bulbs i was thinking by itself i see failure.
Softies i tried turned brown and looked like poo. Wasn't very good growth.

 

[jda]

I did mean the ocean.

Has anybody every gone to the South Pacific to visit, look at coral or even collect? Maxima clams are all about 6-10 feet deep at high tide and less at low in Tahiti. Euphillia and most acros will scrape the heck out of you snorkeling if you are not careful. I have never been in the Red Sea so I have no idea how deep any of those go.

The vast majority of what we keep can be collected in the wild with snorkels. Diving is more fun, but not necessary. Some of the most popular corals are collected in waist deep water - you can go and see this in the south pacific if you want... they will let you go and collect your own coral. hold them and then ship them to your own airport through LAX when you get home.

In the Atlantic, the Ricordea and Mini-Maxi Nems that most people like are less than 10 feet deep in the rubble.

This is a long winded way of saying that all of the spectrum from 350 to about 800 is present in these waters where most of the corals are collected from. There is still a good amount of red at 10 meters... yellow and green down to 30 meters. These inhabitants get almost every bit of a 6.5K bulb.

This is pretty common in the Pacific:

 

[jda]

You guys are talking about running it with other bulbs i was thinking by itself i see failure.

Failure for nearly all, for sure... The coral could do very well, but they will be ugly. Back in the day, it would take 4x VHO Super Actinics to balance out a 5.5 or 6.5K bulb, but the growth and color was phenomenal.

 

[A. grandis]

Failure for nearly all, for sure... The coral could do very well, but they will be ugly. Back in the day, it would take 4x VHO Super Actinics to balance out a 5.5 or 6.5K bulb, but the growth and color was phenomenal.

Absolutely.
Grandis.

 

[BigJohnny]

You have to look at how much of the spectrum of those tubes cover.
As long as there is not to much of one that's bad (like red and possible a couple other ) so who cases about the rest of it if it's only for visual pleasure. The only other concern is algae. But we're talking about coral here.

That Giesmann will grow most all cola just fine by itself , and limit algae and not damage the coral with a red OD.

Honestly I'd have to look at the ati c+ again. It's not very red. Likely due to algae concerns. It def hits some yellow.

Right but don't you think the ati blue + has higher pur than the 6500k since more of it is concentrated in usable wavelengths?

 

[BigJohnny]

I used to run a Tropic 6500K in my two bulb T5 setup to complement my hydra. Its more of a daylight spectrum and my corals including SPS were doing great in terms of growth and colours. I recently changed that with a ATI coral plus 2 weeks back just for experimenting. Nothing drastic yet but will know in few months.

Would love to hear what changes, if anything.

 

[saltyfilmfolks]

Are you saying a 6500k bulb has higher PUR than an ATI Blue Plus or ATI Coral Plus? Sure it contains all the colors they need, but it also contains more colors they don't.

Right but don't you think the ati blue + has higher pur than the 6500k since more of it is concentrated in usable wavelengths?

pur usable. 65 has a lot of usable. You have to Compare to see what has more or whitch one is lacking what.


Varied amounts of each spectrum produce different results , those include growth , and pigmentation changes etc.
And each coral species does react differently to these.

But but the light contains the known Usable NM of the spectrum.

 

[BigJohnny]

I did mean the ocean.

Has anybody every gone to the South Pacific to visit, look at coral or even collect? Maxima clams are all about 6-10 feet deep at high tide and less at low in Tahiti. Euphillia and most acros will scrape the heck out of you snorkeling if you are not careful. I have never been in the Red Sea so I have no idea how deep any of those go.

The vast majority of what we keep can be collected in the wild with snorkels. Diving is more fun, but not necessary. Some of the most popular corals are collected in waist deep water - you can go and see this in the south pacific if you want... they will let you go and collect your own coral. hold them and then ship them to your own airport through LAX when you get home.

In the Atlantic, the Ricordea and Mini-Maxi Nems that most people like are less than 10 feet deep in the rubble.

This is a long winded way of saying that all of the spectrum from 350 to about 800 is present in these waters where most of the corals are collected from. There is still a good amount of red at 10 meters... yellow and green down to 30 meters. These inhabitants get almost every bit of a 6.5K bulb.

This is pretty common in the Pacific:

I know where corals exist in nature, I was referring to where a lot of them are actually collected for the hobby. I don't really want to get into debating that though (I'm sure neither do you), so moving on.

My other point was still relevant, it doesn't necessarily matter what light they were receiving in nature. Just because a coral exists in a certain environment in nature, doesn't mean that we can't create a better one at home (The porites example) and just because they are exposed to all of the wavelengths of a 6500k light source, doesn't mean that they use it all. "full spectrum", doesn't mean it's more for the coral to use. IMO a lot of it is wasted and it's actually a less efficient bulb at growing coral then others specifically tailored to their needs.

 

[saltyfilmfolks]

I know where corals exist in nature, I was referring to where a lot of them are actually collected for the hobby. I don't really want to get into debating that though (I'm sure neither do you), so moving on.

My other point was still relevant, it doesn't necessarily matter what light they were receiving in nature. Just because a coral exists in a certain environment in nature, doesn't mean that we can't create a better one at home (The porites example) and just because they are exposed to all of the wavelengths of a 6500k light source, doesn't mean that they use it all. "full spectrum", doesn't mean it's more for the coral to use. IMO a lot of it is wasted and it's actually a less efficient bulb at growing coral then others specifically tailored to their needs.

Take a look at this though. It's a quick dig and advertisement, but pretty close.
This is what we're targeting with light.

I'll throw this in too.
https://www.reef2reef.com/threads/lighting-spectra-photosynthesis-and-you.100170/

 

[BigJohnny]

Take a look at this though. It's a quick dig and advertisement, but pretty close.
This is what we're targeting with light.

Nice one! Right, so basically 90% of the light from 490-660nm is barely absorbed compared to 370-490......if I'm reading that right.

 

[saltyfilmfolks]

Nice one! Right, so basically 90% of the light from 490-660nm is barely absorbed compared to 370-490......if I'm reading that right.

Correct.

 

[ChrisRD]

Interesting discussion...I do remember a lot of great tanks using Iwasaki 6500K halides back in the 90s...some of the biggest names in the reefing community actually. I think Sanjay Joshi was using them on his home tank and the Penn State tank...some of the best SPS tanks of that era. Anyone remember Venture 5500K lamps? They made the Iwasaki lamps look nice...LOL.

 

[mcarroll]

Different strokes for different folks....not every 6500K light is equivalent or even all that similar, so it's not too surprising that they don't perform equally.

Compared to LED, the base light on a halide or T5 is mercury-green and they have to balance to 6500K from there. You can see that green spike is always there.

The famous 6500K Iwasaki:

Compare with the D65 daylight standard from Radium:

A 6000K halide from Radium:

6500K T5 from Radium:

6500K "Starcoat" Ecolux T5 from GE:

6500K T5 from Giesemann:

The base light on an LED is ~450nm blue. They convert some of that to broad spectrum light.

Even low-Kelvin LED's have a blue spike, but above around 4000K color temperature the blue peak dominates the broad spectrum light like in this Tunze's 6500K LED:

​

All those spectrum graphs are 6500K.

All are different.

For fun and excitement, compare those to the absorption curve @saltyfilmfolks posted.

The famous 20000K Radium for reference:

​

 

[jda]

My other point was still relevant, it doesn't necessarily matter what light they were receiving in nature. Just because a coral exists in a certain environment in nature, doesn't mean that we can't create a better one at home (The porites example) and just because they are exposed to all of the wavelengths of a 6500k light source, doesn't mean that they use it all. "full spectrum", doesn't mean it's more for the coral to use. IMO a lot of it is wasted and it's actually a less efficient bulb at growing coral then others specifically tailored to their needs.

I think that if you had any kind of breath and depth of personal experience with these other lighting sources, you would not think that your point is all that relevant. While it is fun to talk about academically and wonder about, there is no practical experienced-based argument to be made - a 6.5K light will outperform nearly anything else on the market for growth and rendering color... they just do not illuminate the color very well at all and the tradeoff of having so much more wattage dedicated to blue is not worth it to many people. If you take a frag out of a tank lit only by 6.5k light and then immediately put it under a 20K light source, they look amazing.

You probably don't know much about where coral is collected if you think that a sizeable chunk is at 30 meters - the rebreathers and equipment necessary makes this terribly expensive and dangerous and nobody could afford the coral. The guys that we saw have a mask, bag and saw and they hold their breath.

I think that it is OK to admit that we don't know as much about spectrum as we thought. A few LED iterations ago, UV was worthless and you were a fool for mentioning that it was handy. Now IR is making a comeback. Some panels are upping the red, yellow and green. With every new iteration, more and more elements of natural sunlight are being re-added. I know that it is easy to believe a LED manufacturer, supplier or the like with the argument that they can do better than millions of years of evolution and adaptation, but that probably is not the case as much as it is. What we are doing is tailoring the light to our needs since people like the colors under more blue conditions.

 

[Velcro]

If you take a frag out of a tank lit only by 6.5k light and then immediately put it under a 20K light source, they look amazing.

I have noticed that when I get stuff from battlecorals, who runs a lot of 6500K, that stuff looks ridiculously amazing under my 20k for the first week and then fades to less ridiculously amazing and more just regular amazing. When I first get stuff from him is has a crazy glow that I didn't think SPS could even achieve. Maybe I need to just rock some 6500K bulbs in place of a coral plus and blue plus bulb for several hours a day and see what happens!

 

[joshbridges]

Watts my friend ,, corals LOVE WATTS <3

 

[jda]

I have noticed that when I get stuff from battlecorals, who runs a lot of 6500K, that stuff looks ridiculously amazing under my 20k for the first week and then fades to less ridiculously amazing and more just regular amazing. When I first get stuff from him is has a crazy glow that I didn't think SPS could even achieve. Maybe I need to just rock some 6500K bulbs in place of a coral plus and blue plus bulb for several hours a day and see what happens!

Those waves that people think that coral don't need or use sure do some cool stuff, huh? In all seriousness, I had to move to 10K as a compromise since the wattage to balance out a 6.5K was so intense, but this was all halide and maybe a 6.5k T5 or two are in my future since they won't take as much to overpower. IMO, I would run the 6.5K during the whole time that you don't need to view the tank and scale them back when you just want to illuminate - let them go to work when you won't see the more-yellow tint and turn them off when you get home.