Help Orange turned Brown !!!

These were my first sps corals and they have been doing fine for 3 weeks and then all of the sudden the orange monti cap started turning brown and the green birds nest is starting to shed ( which i am assuming it is dying). Everything else in the tank is doing just fine.  Nothing new has been added or changed.  I checked my parameters and here are the results:

75 gallon oceanic half circle
Salinity. 1.025
Temp. 75
Cal. 450
alk. 2.5
Mag. 900
PH 8.2
Phosphates and ammonia are both less than are basically zero.
Lighting: 36 3w cree led

Here are some pics:
1st pic is my tank with mainly blue led on before i added the coral
2nd pic is my tank as it sits now
3rd pic is a close up of the corals that are being affected.

Any help or advice would be appreciated !!!! Happy Holidays lol

basically zero...

Your ALK is really low. It should be 4 mel/q and your mag is super low too. I keep mine around 1400-1500. I bet it's the low Alk though. Birdsnest is really sensitive to water parameter changes. Lighting could be a factor too. What do you have for lighting?

Oh and it looks like there is a 3rd type of SPS in that pic. I'd say all three are too close together.

The rest of the coral look fine so N is not a problem. Even Nitrate as high as 50 ppm is no problem in some tanks.
Soda Ash (baked Baking Soda) is not necessary. Baking soda is all that is needed. We can go into the details if needed.
And for raising the Mg, Epsom Salt is all that is needed.

That is my old rock and coral. I had great growth and color for years out of those corals. I would say that alk is too low and so is your magnesium. Magnesium needs to be kept above 1300 in my experience or you will see problems.

I would also say that the LED's are the major problem. I am not convinced they can keep reef tanks successfully. You will have certain colors and corals suffer from the lack of spectrum.

You can't run only blue and cool white LED's. I believe you MUST run some warm whites to bring in some red. Kind of like the early days with T5's, people were only running only Blue Plus and Aquablue bulbs. Pinks and other colors always suffered. As soon as KZ came out with the Fiji Purple, it changed the game.

Corals need red and blue light the most. The middle of the spectrum (green, yellow, orange) is not needed as much.

lol

Edited by kellerexpress - December 26 2010 at 3:43pm

What I said about Mg is true for the moment. The Mg needs to be raised ASAP along with the Alk. Epsom salt is very safe and Baking Soda is the same exact chemical that costs 10x as much at the LFS.
Ryan is correct after a point. Yes, in the long run Epsom Salt should be moderated with water changes, but there is also a Sulfur Cycle that is often overlooked. We can get to that later.

sjaynes, are you there?

This same thing happened to me 2 months ago. All my parameters were good though. My alk and mag were at normal levels along with everything else. I couldnt ever figure out what it was. My orange monti turned completely brown and so did parts of my green birdsnest. To me it looked like some sort of fungis. What I ended up doing was pulling out all the montipora besides what was attached to the rocks and breaking off all the brown parts on the greed birdsnest. Then I dosed my tank with lugals iodide solution. I dont know if it helped or not but the parts of the montipora that were stuck on the rocks that were completey brown are starting to color back up and im seeing a lot of new growth. I have no idea what it was but your montipora looks just like mine did before it turned completely brown. Good luck.