too much light

[kjswift]

can you have to much light? to close to corals? would it cause bleaching if so? thanks

[Tim Marvin]

Yes, you could. How much light are we talking about? If you have a coral directly under a 400w halide, it could be a problem..

[Tim Marvin]

Well, actually Josh the corals are a different depths in the ocean and are adjusted to that light. The same coral at 70 feet won't do well in 5 feet of water. 400w halide directly over one puts out a lot more light than a coral would get at say 30 feet. Oh, and it depends on the kelvin rate also. Like 10k vs 20k. I just added the 2 retro kits from 360reeffarms, they are actinics, and I swear the corals are coloring up already... It has been a little less than a week. I also run the 2/250DE HQI's as well as the 4/54w T-5's.

[alexwolf]

I bleached everythig in my tank when i swapped a 20k for a 10k. I even killed some things.......pretty rough......

[kjswift]

i am running 2x 250watt 10k's and two 140 watt super artintic's.

[GaryP]

KJ,

That's exactly what I am running in my 125 gal. Where you may have had a problem was in the sudden increase in PAR value. A 10K has a much higher PAR value than a 20K. Just as we have to acclimate corals to changes in salinity and pH, we also have to acclimate them to sudden changes in light. As Tim said, you have to know where a coral comes from on the reef. That's not easy to do. A good coral book will help. Generally, SPS comes from shallow waters. LPS is a lot harder to figure out. It may even vary within a species. For example, a red open brain comes from deep waters and a green one comes from shallow water. This is one of the issues, IMO, in coral husbandry. Unfortunately for our corals its often a matter of trial and error and experience.

You will often see folks recommend starting a coral off at deeper levels in the tank and slowly moving it up towards the top. New corals are often held at an LFS or transhipper at less than optimum light conditions and will need to be acclimated to the light conditions in your tank.

Another thing to remember is that water absorbs different wavelengths at different rates. Reds are absorbed first as you go deeper. Blues are absorbed last. We are trying to recreate natural conditions in an aquarium, but a two foot deep tank is never going to recreate the environment of a coral that was collected from 50 feet. I have a chili cactus coral in one of my tanks that requires absolutely no light. I have it in a cave. My blue mushrooms bleached when I moved my tank and the rockscape was rearranged and they were exposed to full light. Eventually they moved to small crevices where they only get reflected light.

Gary

[Tim Marvin]

well said.