Questions about SPS and Light?

[douglam]

Does the entire coral need to be exposed to equal amounts of light? If a coral is placed on the rockwork at an angle, where part of it is towards the sand or not receiving as much light, will it bleach out and die or does the coral absorb light as one whole thing. I hope that makes sense.

I guess if one part of the coral is not receiving enough light will it die off?

I see all these SPS tanks where corals are shaded by others and it never appears as though the shaded parts are fading or dying.

[kemann]

It is normal to have areas of a coral getting differing levels of light. Unless you are giong to invest is a system to get the lights to traverse across the tank (like the sun), you are stuck with light coming from a single point. The coral growth will generally be influences by the direction of the light as well as the flow of the water around it. As the coral grows, it is not unusual for areas to become shaded and grow slower or even recede. I think that if you were to look closely at some of the great show tanks we see, there are areas that are shaded and not doing quite as well as other areas.

Kevan

[Todd March]

What you mention, douglam, about corals at angles and degrees of shading, or light deprevation, is much more of an issue in halide lit tanks—point source light. With T5's corals tend to grow in different formations (more dense and closer together), influenced by the more spread out and even light source. It's not uncommon for a coral in a halide tank to have a browned out base or lower branches that are less colorful, due to less light getting to these parts of the coral's tissues; the same coral under T5's often shows more even coloration all over, including the base. I read about this before setting up my latest tank with T5's, and it sure is true; even the shaded areas of my corals show nice color...