Sunlight Contribute to Browning Acros?

[h20cooled]

There's a thread in the Advanced forums with people using only natural sunlight to light their tanks and the SPS had great color. So no its not the sunlight...

 

[Bullredchaser]

If sunlight is turning your colors brown someone should tell that to ORA as they grow corals under natural sunlight but there colors are amazing.

 

[Covey]

Actually that is a funny example as alot of the ORA greenhouse corals are farely browned out. They start with good stock and there corals always look better after they have settled into your tank. Check out the photos on the ORA website there not doing themselves any favors.

Dr. Macs grows frags in a greenhouse as well and they shift there stuff inside before to MH lighting before they put it up for sale.

I think pure sunlight in very shallow water will brown corals but the hybrid systems that use sunlight and Actinics hold color well.

 

[epon]

verrry interesting .....

 

[epon]

oh and ...

<a href=showthread.php?s=&postid=9436731#post9436731 target=_blank>Originally posted</a> by h20cooled
There's a thread in the Advanced forums with people using only natural sunlight to light their tanks and the SPS had great color. So no its not the sunlight...

I wandered around that thread and did not think thier tanks had " great color ". Some good color on some corals yes, but the ones I saw looked kinda brown too.

 

[stony_corals]

The only reason an sps would turn brown is due to excessive nutrients causing a greater than "normal" population density of zoox. Zoox can absorb nitrogenous compounds directly from the water column, and hence their population grows resulting in a browning out of the corals. At low levels of NO3 (and other nitrogenous compounds), zoox get these from their host....

So if sunlights turn corals brown, why are there purple/pink/blue ( etc ) corals on the reefs?

 

[epon]

I think it's a matter of how much sunlight it recieves coupled with the particular coral. Another mystery of reefkeeping, kinda like how one sister will be smokin hot and the other not so much ... kinda.

 

[stony_corals]

I think the only difference would be that if the pigments of the coral is actually brown/tan or some variant. Otherwise the pigments would show through as the zoox wouldn't be "in the way".

 

[JB NY]

<a href=showthread.php?s=&postid=9457171#post9457171 target=_blank>Originally posted</a> by stony_corals
The only reason an sps would turn brown is due to excessive nutrients causing a greater than "normal" population density of zoox. Zoox can absorb nitrogenous compounds directly from the water column, and hence their population grows resulting in a browning out of the corals. At low levels of NO3 (and other nitrogenous compounds), zoox get these from their host....
?

I don't know if I would say that is always true. Some colors brown out with a lack of light. I've also seen other corals ONLY do well in higher NO3 enviroments and lighten up and loose their color in a low nutrient tank. Not often but I've seen it a few times.