Metal Halide vs. LED Rates of Photosynthesis

[djf91]

I think we might disagree what accurate means here. Obviously our tanks are not real reefs nor do we really shoot for a real reef. All the dead coral in between the live ones, the predators, the sandstorms and plankton blooms, the sand littered with frags from previous hurricanes, etc. are things we avoid in our tanks. Steve Weast was just on reef therapy where he described his aquariums as "an artistic depiction of nature" and that is also what I seek. There is a difference between an artistic depiction of nature (not "accurate" really) and trying to actually replicate nature.

Yea, I think we will have to agree to disagree. The degree of replication we are able to achieve in each of our aquariums is a spectrum. Yes, I heard Steve say that on the podcast but I disagree a bit. I think we should give some credit to what we achieve with our tanks in regards to an accurate depiction of nature.

Someone who throws concrete boulders in an aquarium, adds saltwater and a few fish and then a few barely surviving corals could call that a coral reef, but I would say it’s a poor reproduction of one compared to something like Steve’s tank.

Someone who has a large refugium, doses phytoplankton, adds live rock from the pacific, etc. is going to replicate a real ocean reef better than someone who doesn’t.

There are certainly a lot of variables, many that we can’t reproduce, however there are also many boxes we can check to create a more accurate replication of what happens in the ocean.

 

[minus9]

I think we might disagree what accurate means here. Obviously our tanks are not real reefs nor do we really shoot for a real reef. All the dead coral in between the live ones, the predators, the sandstorms and plankton blooms, the sand littered with frags from previous hurricanes, etc. are things we avoid in our tanks. Steve Weast was just on reef therapy where he described his aquariums as "an artistic depiction of nature" and that is also what I seek. There is a difference between an artistic depiction of nature (not "accurate" really) and trying to actually replicate nature.

Agree, we are creating an artificial reef in a glass box, so each person's depiction will be different. It is our "artistic" approach or view, which may not jive with others, but that's okay. The way we use "natural" will be vastly different, which is subjective to the end user.

 

[Nonya]

I may sink a toy Russian cruiser in mine and call it an artificial reef.

 

[Nonya]

Agree, we are creating an artificial reef in a glass box, so each person's depiction will be different. It is our "artistic" approach or view, which may not jive with others, but that's okay. The way we use "natural" will be vastly different, which is subjective to the end user.

I'm ok with a fruit stand, but the new one will have more of a bonsai-type arrangement.

 

[BradB]

So I was wondering. Corals in nature experience

I have my LEDs programmed for varying spectra from dawn to dusk, somewhat simulating actual lighting on real reefs. Mid-day is closer to the AB+ with more white, but no red/green. The rest of the day is a transition from/to dawn and dusk, with all blue and violet. If I'm going to spend too much time looking at the tank, I usually wear eye protection. BTW, the eye damage can come from any bulb with a strong blue spectrum.

Spectrum on a natural reef varies very little depending on time of day.

Anyone worried about damaging their eyes from blue light should be aware that is the total amount of blue light that counts, not spectrum. If 400 watts of royal blues over your tank is bad for you eyes, so is 400 watts of royal blues with 800 watts of white added.

 

[BradB]

I think we might disagree what accurate means here. Obviously our tanks are not real reefs nor do we really shoot for a real reef. All the dead coral in between the live ones, the predators, the sandstorms and plankton blooms, the sand littered with frags from previous hurricanes, etc. are things we avoid in our tanks. Steve Weast was just on reef therapy where he described his aquariums as "an artistic depiction of nature" and that is also what I seek. There is a difference between an artistic depiction of nature (not "accurate" really) and trying to actually replicate nature.

IMO the biggest difference is light changes directions on a real reef, but always comes from the same place in our tanks. This has dramatic differences in the growth of corals like Acropora that grow towards the light.

Very diffuse blue LED is going to replicate 100 feet below sea level a lot more accurately than bright white stationary halides replicate 10 feet below sea level.

 

[oreo54]

Spectrum on a natural reef varies very little depending on time of day.

Anyone worried about damaging their eyes from blue light should be aware that is the total amount of blue light that counts, not spectrum. If 400 watts of royal blues over your tank is bad for you eyes, so is 400 watts of royal blues with 800 watts of white added.

Define very little.. The light field "color" varies constantly..
Pure blue 10000k sky, cloudy 5500k sky, Sunrise/sunset 3000k sky..

You need to be careful w/ that assumption the "blue" that is being considered.
AFAICT it isn't ALL blue.
Actually also the violet range is err "exempt".
High energy short wave blue light between 415 and 455 nm
You could use RGB w/ "windex blue" diodes to make white.
460-470nm.

You are correct that most current LED whites use Royal blue with a higher nm of 460.

 

[Nonya]

I may sink a toy Russian cruiser in mine and call it an artificial reef.

 

[BradB]

Define very little.. The light field "color" varies constantly..
Pure blue 10000k sky, cloudy 5500k sky, Sunrise/sunset 3000k sky..

You need to be careful w/ that assumption the "blue" that is being considered.
AFAICT it isn't ALL blue.
Actually also the violet range is err "exempt".
High energy short wave blue light between 415 and 455 nm
You could use RGB w/ "windex blue" diodes to make white.
460-470nm.

You are correct that most current LED whites use Royal blue with a higher nm of 460.

Very little means the color temperature is the same and you probably won't notice a difference with your eyes, but there is a difference that can be measured.

The center of the spectrum stays the same, but at dusk and dawn, you lose a little off both ends. So less red and less violet. The 'all actinic' look people assume happens at sunrise and sunset doesn't exist at all.

Above and below, you get bluer light with less yellow when the sun goes behind a cloud. But this is much more noticeable above.

 

[oreo54]

Very little means the color temperature is the same and you probably won't notice a difference with your eyes, but there is a difference that can be measured.

The center of the spectrum stays the same, but at dusk and dawn, you lose a little off both ends. So less red and less violet. The 'all actinic' look people assume happens at sunrise and sunset doesn't exist at all.

Above and below, you get bluer light with less yellow when the sun goes behind a cloud. But this is much more noticeable above.

Much probably depends on how deep you go..

Spectral Data from a Shallow Hawaiian Tidepool

Dana Riddle previously documented and discussed light intensity of a Hawaiian tidepool versus the home aquarium. Dana continues his light analysis by examining spectral data. What can nature teach us about coral care?

reefs.com

 

[iquitreef]

Hard to beat t5