Acro/Monti color change

Possibly... But I am just not thinking light is the case. Maybe I am wrong though. The big tip off for nutrients to me was the turquoise color on both the RP and the plum crazy, as well as the browns on the other acros. ORA corals turn green when there are nutrients present. Other acros will go brown or green also.

 

One note on the browns- those were a couple small colonies a guy sent me and one shattered in the bag. They were already brown when I got them. I mounted the three little pieces on plugs and the one colony and the three frags all bleached their tips within a few days. After a week or so the color was coming back and they are just a bit darker brown than when they arrived. That, to me, was pretty a obvious light issue. The others never bleached their tips- they just changed color completely.

 

I was just closely examining the corals again and noticed that the "brown" ones I received are now turning orange with a hint of blue in the tips. The Plum is now much more blue but the Red Planet is also turning orange as well. The color on the RP is more orange on the underside of the plug where is has encrusted. Perhaps this is a step toward acclimation?

 

Interesting...I had some monti digitata that I receive brown, and it started growing brown, but when I added a light with more purple spectrum (in addition to the actinic) it started growing purple. I don't know if it was the additional light or the additional spectrum.

 

The it very well could have been light acclimation?

 

Whether to light or nutrients, or both, it is probably adjusting. One thing to remember, is light and nutrients are related. Zoox can't grow without light or nutrients. With light and nutrients, you get zoox growth and browning, or if too much zoox growth, then the coral expels zoox and you get bleaching.

On the other hand, too little light and nutrients, zoox doesn't grow as well, so, either the coral will allow more zoox, in it's tissue, to make up for the reduction in energy output from the zoox, or the zoox will die of and the coral will become pale.

So, actually, in theory, you can get browning OR bleaching, from too much OR too little light/nutrients.

Narrowing down what is happening can be tough, but lightening tends to have to do with too much light, or better stated, an inability of the coral to adapt to the lighting, spectrum or intensity, fast enough to prevent damage to the coral or zooxanthellae.

Based on my experience when switching to very blue intense lighting, light shock is more likely. It's always good to acclimate to light slowly. Perhaps there are nutrient issues as well, but how do you tell unless you first rule out light? The end result can be the same. Red Planet acros for example, tend to turn green under low lighting IME and according to Dingo, when nutrients are present. I wouldn't be surprised if both were true, as there is a fair amount of overlap between light and nutrients.

 

Purple corals tend to look brown if there is not a lot of deep-blue light IME. If the change was instantaneous, I would guess it is just the light changing the visual perception of the corals colors. If it was a slow change, then more light/spectrum. Most corals produce pigment in response to intensity, and often of in response to intensity of a specific spectrum, if that makes sense?

 

Great link-Thanks! I had read about the screen technique elsewhere and figured I will give it a try under my second 36" fixture as I cannot add single bulbs.