Coral light absorption

[cocoacf]

Say you have 10 watts per gallon of water. If a certain type of coral requires say "5 watts per gallon" and you put it in your tank... does that mean it is taking up 5 watts per gallon and you only have 5 watts left?
Also, do corals absorb light energy from the water even if they are in direct contact with light? For example would GSP be able to grow under a ledge in the rock work that has no light shining on it?

 

[wangotango]

Watts/gallon is irrelevent and won't tell you anything. 6 watts/gallon of PC is not nearly as powerful as say 4 watts/gallon of T5ho or halide. Corals don't absorb watts so, no if you have 10 watts/gallon and two corals that "require" 5 watts/gallon each then that would mean there's no light left...
The zoanthellae algae in the tissue use the light for food (like chlorophyll in a tree). If a coral needs light (photosynthetic) then blocking the light from hitting it is going to starve the zoanthellae. May not kill it, but probably wouldn't thrive.
-Justin

 

[reefkprz]

No and no
watts per gallon is about as useless a rule of thumb as was ever invented. its just as useless as the "inch of fish per gallon" rule. both are meaning less. the amount of watts, a lighbulb consumes has little effect over various types of light as to how much light intensity (par) they actually produce.
try and forget the WPG rule and do some reading on various styles of lights and their pros and cons.

 

[t316]

Forget everything you have heard about watts....
What type of lights do you have?

 

[cocoacf]

150 watt HQI.. It's over a 29 biocube. Not really interested for any particular reason.. just wondered.
However, for the second question.. I did have GSP on a rock and it has a little bit under a cave that gets no light so I was curious as to whether it would die or keep spreading under the rock.