Coral coloration FAQ

[Rebels23]

Ok thanks Eric! Sorry for being a knuckle head on this. I think I wasn't clear before.

When I say 'darker' I guess what I was thinking of was what I refer to as the coral "browning out". Brighter or Deeper colors I guess the way you are describing, I would have no problem with.

i.e. My green monti Cap is now a deeper green or a brighter green, but not brown.

I am afraid if I under skim, my corals will brown out because of excess nutrients. I am not sure what the effects of over skimming would be, brighter, deeper, brown colors??

Ok, I relaized I just sounded like a babbling idiot. lol

Rebels23

 

[crlkeep]

What I gather from the results I have seen in my tank is that if you "over skim", you may actually remove not only vital Nitrogen compounds, but micro organisms and algaes that may also serve as food. This effectively could result in starving the animal.

If you "under skim", and your system is not capable of processing all that your skimmer would normally be removing, then you may cause harm to tank with an excess of these nutrients.

It makes good sense to me, but without more testing on the levels of nutrients absorbed or otherwise attained by these animals, it is hard to say what is best overall. Since most of our corals come from many different reefs, they likely have very different needs.

 

[joereefer]

i bought an open brain coral last week from my lfs,i noticed that it appears to be bleaching. its under a pc 2- 96 watt bulbs. what do you think is going on?

 

[Rovert]

Eric, thanks for the great read! I'm often asked by friends what makes corals so colorful, and have to stammer through the "pigments to protect the photosynthetic organism" speech. Now, I can just hand them a copy.

Now, here's my question.

A while back, there was a hypothesis going around that suggested a correlation between coral coloration and alkalinity levels. What's your take on that?

 

[EricHugo]

well, a hypothesis is a tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation - as far as I know, this hypothesis has never been tested, and remains a weak anecdotal observation...

my feeling is that higher alkalinity spurs faster growth and hence longer growth tips that are low in zoox but high in pigment, lending the appearance of being more colorful. Personally, I don't think there is any correlation between the two.

 

[ktm]

Nutrients

Nutrients

Nitrogen

Hi, I have the same problem of Acros turning dark brown. I'm suspecting high nutrients. I'm using 250W 20K MH abt 18" from the corals. My bioload is very low(only 4 small fishes) for my 3ft tank, but I do feed the corals daily with a pint of golden pearls and cycloeeze.

When you say high nutrients it means high amount of Nitrogen inside the water right? Is it the excess waste or food that are not eaten decompose and release as Nitrogen in the end?

Could the daily feeding be the cause of the high nutrients?What are the methods available to reduce the nutrients level? What immediate action should I take?

Thanks a lot,
KTM

 

[EricHugo]

KTM:

The first thing is perhaps to get the corals or the light a little closer to the water surface?

As far as nutrients in the water, they are the product of animal and bacterial metabolism as well as food and water inputs.

What are your levels?

 

[ktm]

browning

browning

Thanks for the speedy reply Eric,

The 250W 20K MH is 5" from the water surface & the distance between the water surface to the Acro colony is 13". So its abt 18" from the light.

My NH3,NO2,N03 are all 0ppm, Ca 500ppm, DKH 10, Phosphate 0.1ppm.

Tank size 36"x18"x30"
2 x 250W 10K & 20K MH
Weekly drip of 2L kalkwasser
Daily feeding with phytoplankton,Cycloeeze & golden pearls.

All other corals seems well but do not know why the acro turn brown. I do have a tri-color acro frag that has coloured up from light brown to darkbrownish purple with green polyps, they are ard the same height under the 20k MH.

p/s: I do not have a refugium, just a simple wet-dry sump tank with protein skimmer.

 

[EricHugo]

Depending on the coral, the 250 even at best may not be enough, but 18' from the bulb and you can pretty much fuggetaboutit. Move it up,, increase water flow, get rid of the phosphate, and add some carbon. I have several species near the very top under 400W bulbs that will turn blue and purple but only when thebulbs are clean and fairly new...that's how close I am to minimal irradiance level needed for these corals...others stay blue or purple at much lower irradiance levels.

 

[MacnReef]

Eric, I have a question.

My orange monti cap has grown very big in the last year but in the last few weeks it seems to be taking a turn for the worst. The underside of the corals has some green spots on it, like an algae and the color of the coral is getting a little lighter in some areas on the top. Last night I flipped the coral over to see the bottom and the bottom is almost solid white.

Do you know what may be happening or what I can do to help the coral?

Thanx Mike

 

[crlkeep]

It may be that the monti has actually grown large and thick enough to block out light that may have been able to reach the underside. Since the light is no longer reaching the underside, the coral may be slightly starving as it is not recieving enough food.

What are your current levels for: pH, alk, Ca and Mg?

 

[The Escaped Ape]

If more light in nature produces pigments like pink and blue (and hence we should try and recreate that to preserve these colours), then are there similar guidelines for other pigments? I have a yellow acro (LFS said A. Selago) that has browned up under my 2X250W 10Ks (not DE). Currently it's sitting about two thirds of the way up the tank (I had all sorts of dire warnings from the LFS that moving it from the 20K lamps it was under to 10K lamps might burn it or turn it brown). Any idea whether I should move it further up/down? It's only been in there for a couple of weeks, so I realise I have to be patient.

 

[MacnReef]

CA 435
Will test Alk tonight
pH 8.1
Mg 1440

Mike

 

[crlkeep]

Those numbers look acceptable to me Mike. Unless your alk is way out of whack, then we can eliminate the easiest tested causes right off the bat.

Aside from your normal maintainence routines, have you made any changes to this tanks setup in the last couple months. ie. new livestock, substrate, switch salt brands, etc....

Trying to get a better idea through the process of elimination...

 

[MacnReef]

Well I know you are going to say, well duh, that is the problem but a month or two back I switched out my old sump which was a 30l glass tank with dividers. It had a small protein skimmer that didn't really work all that well and a refugium that was about 20"x10". The fuge was full of caulerpa and I was running a reactor, but too much CO2 was returning to the tank and feeding the caulerpa, so when I took out the *reactor, the caulerpa died so now I have a acrylic sump with a 100 micron bag that I run constant for the first month because the tank had a lot of floating debris and I run a CS6-1 skimmer and a external blueline pump.

*I took the reactor out because the original substrate I had in the tank turned into a solid piece of concrete because of the reactor. It was almost impossible to remove it, then when I put the new substrate in(mind you this was a few months back on the sand change) it stayed fine but I was getting this build up of calcium on the walls that was solid white and almost impossible to scrap off. I came to the conclusion that the reactor was causing this and when I took it off the caulerpa died so I had very little filtration. So I felt I had to make the change. Plus none of the other corals are reacting to the change.

Mike

 

[MacnReef]

Here is the under side of my cap...

 

[MacnReef]

Actually it is getting better, some of the color is coming back. The back was solid white.

Mike

 

[tatuvaaj]

Eric,

Since you have seen a lot of different reef environments, can you say that one reef has more colorful corals than the other?

In other words, do you see any kind of relation between the nutrient levels and coral coloration in wild?

TIA!

 

[EricHugo]

Hi Tatu:

You know, that''s a good question. In general, in turbid areas and nearshore areas, you see mostly brown and some greens. On clear outer reefs, all the colors. But, some of the upwelling sites where nutrients can be really high but are well washed and swept you also see incredbile colors.

 

[RonSF]

Thanks for the thread, Eric.
I have a question or two: Do the zoox reproduce along with the corals, in a perpetual symbiosis? There's a bit of a chicken and egg situation, I assume, but presumably at some point the coral existed first, then the zoox arrived. Similarly, what happens when a bleached coral seems to regain it's zoox (perhaps there are always a few that remain to regenerate)? Can they migrate in the current or do they generate a spore like state as anaerobic bacteria do to survive in oxygenated conditions when necessary? If they do sometimes migrate, are there ever cases when differently colored, but otherwise identical colonies mix colors? I've never heard of it, but wonder what mechanism would either facilitate it or prevent it.
-Ron