Browning problem

[JAG107]

I seem to be having a problem with my SPS (acro, birds nest, monti) turning brown from their original purple/pink/green colors (respectively). One Monti however is growing relatively quickly and maintaining beautiful colored polyps. Any Idea What might be causing this? I'm using x2 250w 15k MH w/ x4 65w 460nm actinics. Nitrates are between 5-10 and phos is always zero. Any ideas anyone?
The Birds Nest is also showing bleaching from the base of the colony moving outward.

[reeffreak]

It sure sounds like you have plenty of light and most likely the correct spectrum.I've read that many wild colonies and maricultured acroporas tend to brown out regardless of how good the lighting.That's one of the reasons I always look for aqualcultured acros because they are third and fourth generations(or more) so they are use to artificial lighting.One other thing,the chemicals soft corals release also brown out SPS corals.

[fatman]

The color in corals is from what are called Fluorescing Proteins (FP) that are developed to reflect or other wise manipulate light. As your light appears adequate there is the issue of whether or not you are feeding your corals. Typically most corals only recieve enough energy from there tissue algaes to survive, meaning that they need food other than that supplied through the symbiotic relationship they have with their zooanthellae. When they do not get this food they often shed their FP so as to provide more light to their zooanthellae. Most of the food they need they get from nitrogen based nutrients that come from fish detritus dissolved in the water. They absorb itthrough their tissues. They also feed on small zooplankton taht their small polyps are able to capture. Unless your Monti is placed lower in the tank where it is benefittingfrom incresed amountsof zooplnkton and dissolved nutrients I have no suggestionas to why it is still doing well. I would try at least every other day stirring just the top of your substraate gently and then feeding zooplznkton. Turned off skimmers and any other filters during this time but leave circulation pumps running. SPS do not target feed but must be flood fed, meaning feed a lot then circulate and skim real well to remove all they do not eat.

[ccCapt]

What are your ca, alk and mag levels?

[JAG107]

Actually the montis are all high up in the tank, and I just moved the birds nest to the bottom, thinking it was too bright up at the top for it. It was about 8-9" below the bulbs, now its 20".
Don't know the mag level, but calc is always between 400-440, and alk is a little low--around 7 or 8 deg. (I think thats 125-140)
I also feed wet zooplankton from a jar 3 times weekly, and I switch between cyclops and coral food in frozen cubes (about 2 each per week).

[McCrary]

Browning of SPS is usually caused by stress and I would be willing to bet in this case that excess nutrients and phosphates might be playing a role.

Phosphates are the limiting factor for algae growth, this includes the zooxanthella that are the sybiotic partner for SPS. If you add nutrients and phosphates the coral tend to "brown" because of the increased zooxanthella that are in the coral. When nutrients and phosphates are reduced SPS tend to get lighter in color and they also tend to become vivid as their color is not masked by lots of zooxanthella.

Fatman is dead on when he said that the coral do not get everything from the sun, they also need nutrients. In your tank I am betting that you may have too much rather than too little and feeding the coral food and such probably isn't necessary. Your fish poo is probably enough for the coral.

The reason that I say that you probably have too many nutrients phosphates is because of your elevated nitrates. 0 is the goal for SPS tanks and when nitrates creep up toward 10 you are going to see it in your coral. Also, unless you are testing with a Merck liquid test or a colorimeter it can be extremely difficult to determine phosphate levels in your tank. Running GFO in a reactor should keep them under control and changing the media on a schedule should allow you to go without a test.

I would cut down on feeding and increase the amount of water that is changed and you should see some results. You may also want to run carbon to eliminate the chance that there is something in the water.

[JAG107]

Thanks a million, McCrary. I'll up the water changes from 10%/weekly to maybe 15-20%. My nitrates spiked to 20 over the weekend, sounds like I do indeed have an excess of nutrients.

[McCrary]

No problem, get the nitrates down and reduce your phosphates and I bet you will see improvement. You are probably also high in dissolved organics which can be harder to spot and usually require upping the water changes as well. What kind of skimmer are you running (I'm guessing its for your 110)?