After effects of Alk spike?

[broke1]

I had a nasty Alk spike several months ago where it reached 15DKH+. Most if not all the corals no matter how hard they were hit have returned to their normal growth rates except one. This one made it through everything just fine. Now that the tank has been stable for at least three months at 8.5 to 10 DKH this one is started to show signs of what I would say would be Alk burn. What gives?
http://i72.photobucket.com/albums/i171/BROKE2/42808248.jpg

[Znut Reefer]

Looks like fish nipping. What fish do you have?

[broke1]

If it is fish nipping, I have a Flame Angel that would make the top of my list although I have not witnessed him doing it.

Two Hippos
Sailfin Tang
Yellow Tang
Radiant Wrasse
Two Percs

[dvanacker]

looks like alk burn....if you have corrected the problem you can only just keep it stable and wait.

[Znut Reefer]

I'd keep an eye out for the nipper. Also could be one on the tangs. They are also well known nippers.

[kirstenk]

Where's your PO4?

That looks like what happened to many corals in my tank when it became PO4 Limited.

[Don-Coraleone]

alk burn...

[broke1]

When you say Po4 limited, does that mean low? I have no idea what it's at as my test kits always read zero, yet I get outbreaks of Bubble Algae which are obviously feeding off of it. I would say this looks like Alk burn, but it's the only doing it out of 100 Sps and this started 3 months after the Alk was stabilized.

[kirstenk]

It means 0.00 on a colormeter.

I tested against 3 different meters so I knew I had zero PO4 but I figured my corals were suffering from Alk burn or something else. Eventually I tried dosing PO4 and my corals responded very well.

I threw it out here cuz I see people with problems from time to time with no solid explanation. The low nutrient systems we strive for can sometimes be harmful. jmo