Lighting... do you think we OVERDO it?

[RichReef]

Yes I think we overdo it.

After having my Razor for 5 years now I get the best look and growth at 25w and 80b.

I may not even need the white but that's the look I like.

 

[JustAnotherReefer]

don't even touch the whites on the XR30s.

Blues and UVs the entire way.

 

[Phycodurus]

i’m curious if clams benefit from an emphasis on blues ... certainly Derasas and Squamosas, and i’m guessing Maximas might too ... even if it’s at the expense of the visual appeal that is so attractive to Maximas. Croceas & Hippopus probably are negatively affected??

(graph from https://www.advancedaquarist.com/2011/3/inverts)

 

[Hermie]

http://www.reefkeeping.com/issues/2006-05/sj/index.php

 

[KenO]

Following

 

[Flippers4pups]

These explain a great deal of what PAR we need and spectrum needed to grow most corals we keep.

 

[greg 45]

For what its worth I have a big blue squamosa clam under 600 watt red leds in my refugium and its the best it ever looked .

 

[Dana Riddle]

For what its worth I have a big blue squamosa clam under 600 watt red leds in my refugium and its the best it ever looked .

Congrats - glad that's working for you. I would caution that what works with a clam might not apply to a coral, especially those with thin tissues covering a reflective white skeleton. There are several reasons - the squamosa is reflecting blue light, hence some of it is not available for use in photosynthesis. Second, Tridacna mantles tend to become thick as they age and self-shading by zooxanthellae is possible. Last, red light is known to play a part in regulation of zoox densities, and partial bleaching is not always apparent to the human eye - I used a $2,500 chlorophyll meter to determine this. Again, congratulations on your success.

 

[greg 45]

Congrats - glad that's working for you. I would caution that what works with a clam might not apply to a coral, especially those with thin tissues covering a reflective white skeleton. There are several reasons - the squamosa is reflecting blue light, hence some of it is not available for use in photosynthesis. Second, Tridacna mantles tend to become thick as they age and self-shading by zooxanthellae is possible. Last, red light is known to play a part in regulation of zoox densities, and partial bleaching is not always apparent to the human eye - I used a $2,500 chlorophyll meter to determine this. Again, congratulations on your success.

Dana thanks for pitching in on this. I did try two 300 watt red leds over main display with sps and anemones and didn't see any ill affects. Algae did start to show up so I didn't not continue with my testing on the main tank . I will be moving my Gigas clams over next, Wish me luck . You know more than me on this subject.

 

[Dana Riddle]

Dana thanks for pitching in on this. I did try two 300 watt red leds over main display with sps and anemones and didn't see any ill affects. Algae did start to show up so I didn't not continue with my testing on the main tank . I will be moving my Gigas clams over next, Wish me luck . You know more than me on this subject.

Keep us posted - interested in hearing your results!

 

[Phycodurus]

dana, thank you for your replies to this thread.

may i infer then that a tank heavy on blues is likely not healthy long-term for tridacnids?

 

[jda]

Tridacna can also grow massive amounts of Zoox for shading and then later digest them... corals cannot. Zoox has a more complicated relationship with Tridacna where they can both supply food and become food.

I have never seen corals reactor poorly to more high quality light. They can react poorly to poor quality light. When I land wild acropora, they go into 1000-1200 PAR of 6500k Halides. They thrive. These same coral would die under 400 PAR of LEDs.

I also plumbed a vat outside in the summer for a few years when we lived in Missouri and the corals a few inches under the water in the sun grew exponentially faster than the ones in the tank.

I think that quality is overlooked most of the time in these discussions because quantity is easier to understand and measure. I think that we overdo it with underdone lighting sources.

 

[blstravler]

These explain a great deal of what PAR we need and spectrum needed to grow most corals we keep.

Really informative video. Before watching I thought differently about PAR and always thought more was better (>300) but as it turns out that’s not always the case!

 

[Dana Riddle]

dana, thank you for your replies to this thread.

may i infer then that a tank heavy on blues is likely not healthy long-term for tridacnids?

No, I don't think high intensity blue light is harmful to those Tridacna species accustomed to high light (crocea, maxima.) I did some fluorometer work when in Hawaii with Tridacna (with permits from the State) and didn't see any photoinhibition up to PPFD of 600 or so. Later, I found a thesis that found no photoinhibition up to about 1600 (of the top of my head.) There has been a lot of research on high intensity red light on zoox populations in stony corals and it was found to have negative effects. However, there has been no similar research with Tridacna clams.

 

[Dana Riddle]

IMO any coral reaction takes at least two weeks to whatever modified in a tank (light, flow etc.). Your ideas?

On another note, I was looking at zooxanthellae/chlorophyll concentrations when dosing iron and took non-invasive chlorophyll measurements daily. There were some problems with lighting hence PPFD was non-consistent. Surprisingly, chlorophyll content responded within a day (either up or down.)

 

[fredk]

...

I think that quality is overlooked most of the time in these discussions because quantity is easier to understand and measure. I think that we overdo it with underdone lighting sources.

Spectrum is easily measured with the right equipment and we know what spectra various chlorophyll types make best use of. Do we really know what constitutes a good 'quality' of light for corals? Do we know how sensitive or insensitive they are to different spectrum mixes?

 

[Dana Riddle]

Spectrum is easily measured with the right equipment and we know what spectra various chlorophyll types make best use of. Do we really know what constitutes a good 'quality' of light for corals? Do we know how sensitive or insensitive they are to different spectrum mixes?

Spectral quality and light intensity cannot be examined and reported independently with much success. Excessive red light will reduce zooxanthellae density/chlorophyll content. Excessive blue light induces the protective xanthophyll cycle (which shunts blue light away from Photosystem II.) Same for many chromoproteins and fluorescent proteins. The Advanced Aquarist site is down at present. Once it's up, I'll send a link examining spectral quality/intensity on growth rates of the stony coral Porites.

 

[jda]

The only way that I know how to even get close to finding about good quality is to use a bunch of different lights for a decade, or more, and observe for yourself... or to look at the long term results of very experienced people with your own eyes (photos do not do it right).

I know that the sun is good quality because I believe in the Scientific Method where nature is the best until proven otherwise. From there... it gets fuzzy... but with enough experience, it is easy enough to tell that some lights do certain things differently.

 

[W1ngz]

I was thinking about this thread yesterday after reading it the first time, and I sort of wonder why reef tank lighting isn't based on ocean depths. A reef underwater in midday sun is going to get the same intensity and same spectrum, the only real variable (discounting seasonal changes and cloud cover) is depth. There is no reason at all for any reef light to have a fully adjustable spectrum of 7 different colours and intensities, it's a reef tank, not a nightclub!

Why isn't there some sort of standard to equate reef tank lighting with standard ocean depths instead of these over complicated debates about the best par and spectrum? Corals should come with some sort of information about the depths that they were originally collected from, and where they thrive most. They evolved over millions of years that way, so getting the numbers from a range of 20 to 100 feet deep really shouldn't be that complicated.

 

[jda]

Not too many people would want their tank to look like the ocean where the stuff in your tank is collected. Nearly all inverts are collected on one breath in less than 10-20 feet of water. The temperature there is about 6500k, or so, just slightly less yellow than the 5000-5500k ish color at the surface. Fish get collected deeper and using scuba, rebreathers and the like since they command a LOT more money... and even still 100 feet is pretty deep for this to chase around fish.

Some super rare fish (to the hobby) are collected at 50 meters, but they are VERY expensive due to the risks and stuff. Peppermint Angelfish are like this at $20,000+... nobody would go down there to collect a coral for a few dollars when they can get them in waist deep water or just using a mask.

It was not until LED companies started to sell blue-based light that they were trying to mimic a reef at 50 meters, or whatever, saying that this was more "natural." They also used a few narrow studies of a few proteins to support their narrative. This is a new phenonomen that people believed too much. It is too bad that warmer diodes were so harmful to coral back in the early days. The bottom line is that nearly everything in your tank (and possibly everything without the "nearly") was originally collected under the equivalent of a 6500k MH or T5 bulb in nature. ...so natural is not what people are after.