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Hi all. I have few pcs of RBTA for sale which i managed to remove from the liverock which i discard during decomm. i probably have 4~5 pcs after reserved 4 for myself. The size is from 20cents to 50cents. Is still adapting in my new tank. Deal location Punggol. Selling sgd10 for small pc and sgd20 for bigger pc.

Florescent Proteins While zoox supports life functions of coral, and gives it the much dispised brown color, the florescent proteins (FP) are the reason why we try so hard to keep corals in our aquarium. FP are complex molecules which require a lot of resources to produce. If coral pays hefty price for these proteins, they don't do it just to please our eyes. In fact, FP are essential for coral to survive. FP and Zoox One important reason for the existance of FP is that zoox are very selective when it comes to the type of light it can use. As it turns out, zoox can only make use of light of certain wavelength (can think of it as color). The wavelengths of light useful for photosynthesis is called PAR. PAR spectrum (https://images.app.goo.gl/v49E7u1a1N1ZADo87 Wikipedia ) The light energy unabsorbed by zoox are wasted, or worse, can cause photo damage to the coral tissue. Fortunately, coral evolved a mechanism to deal with this two challenges: Florescent Proteins. Spectrum Shifting and Light In a nut shell, FP absorbs a light of a certain wavelength (this is called excitation), then release the light at a longer wavelength (called emission). This achieve two goals: 1. When the wavelength of the light is increased, the energy of the photon is lowered. So even if the light is unused by the zoox, it will not cause too much harm to the coral 2. When the re-emitted light is at the correct wavelength to be used by zoox, the light energy is not wasted, and coral will gain more food in return. Therefore, it is not difficult to infer the factors which drives the coral to produce FP, and achieve amazing colours. The light must be intense enough such that corals require protection from photo damage. The spectrum of the light needs to be predominantly of lower wavelength (higher Kelvin rating) so that they allow the FB to shift the wavelength up. Hence we arrive at standard reef lighting formula : bright, blue dominant light. [Interlude: for modern lightsets, even for day light appearance, the spectrum is still very blue. Our eyes are not sensitive to blue lights. Therefore even with the elevated blue channels, the aquarium can still have the daylight appearance] The advent of LEDs brings about a second challenge. Unlike MH or T5, the spectrum of LED light sets are the combination of each diodes. These diodes have very narrow emission spectra. Therefore, although a led light might follow a certain spectrum profile, it is possible for some wavelengths to be very weak, or even nonexistent. If the excitation wavelength for a particular FP is absent, then such florescece will not be observed. I believe, when it comes to coral fluorescence, the most important factor is the light. Of course, the coral must be healthy. Building Florescent Proteins Many reefers have read about the trace elements. Iron for green, potassium for red, iodine for blue etc etc. Like wise, reefing products reinforce this idea and have various "color" additives based on trace elements. With all these information, it's fair to assume that these trace elements are in the FPs, right? Turns out this is very far from the truth. The animation below shows a typical green fluorescent protein (GFP). (GFP Movie showing entire structure and zoom in to fluorescent chromophore. (Erin, https://en.m.wikipedia.org/wiki/Green_fluorescent_protein#/media/File%3AGFP_Fluorescent_Protein_Movie.gif) The exterior of the protein is a structure called beta-barrel (green). This structure shields the central chromatophore (yellow) from the surrounding environment. The chromatophore is responsible for the florescence, while the beta-barrel minimizes effect of interference from surrounding environment. Where are the trace elements? Is there an iron atom/ion in the chromatophore? Turns out there is none. There is no heavy metals of any kind in the FPs. Even more surprising, is the fact that many of those "trace elements" can have a chemical quenching effect, dramatically reduce the florescece of the FPs. What is needed for FP building, is amino acids, not trace elements. The Paradox Therefore, the paradox. On one hand trace additives are not a part of FP. On the other hand, adding trace additive improve the color of the corals. Why? I'm puzzled. Could any one suggest a possible theory?

Picked up much from your well-written article. Thank you very much!

Both sold

Coral Fluorescence Coral fluorescence is one of the topic which puzzles me greatly. The florescent proteins and zooxanthellae density are all well studied. But what we do in the hobby, or rather, what works in our hobby, is not well explained by the science behind coral fluorescence. I will attempt to compare the science with practice, then perhaps we can see if there is any missing pieces of the puzzle. Coral Fluorescence in Hobby When it comes to reef keeping hobby, the ways to achieve good fluorescence for corals, especially SPS corals, are well established. We start with water containing very low level of nitrate and phosphates. Then we attempt to keep the pH high, and the "big 3" elements stable. Next, we use intense light and vigorous flow. Finally, we feed the coral, with planktonic mix, amino acids, and dose trace elements to achieve shining color. For most of us, this works well. Some of these factors are easy to understand. Having stable water parameter close to the reef environment definitely reduce stress for the corals. Giving suitable food in the form of planktons and amino acids ensure corals have sufficient nutrients. The intense light encourage the formation of florescent proteins to protect the coral. All these are well and good. The problem is with the trace elements. On one hand, dosing trace elements (such as FM colors, Redsea ABCD) leads to improvements in coral color for me (and many others); on the other hand, the idea that trace elements is needed by the corals to form florescent proteins is highly debatable. In the next post I will list down some facts, maybe one day we can truely know the mechanism of coral fluorescence.