Receeding colony

[Wrench]

Every few weeks I lose a colony to whatever is going on and I need some help figuring it out. I first notice it when a small section of the polyps will close up. Upon closer inspection, the mat is noticeably brown and deteriorating. The stalks of the polyps are also browning and many appear to be pinched, about 1/3 of the way up the stalk. Tissue flaking is also present. Freshwater and iodine dips don't do it. The only thing that works is to remove the infested part of the colony to save the rest. Any ideas on whats causing this?

80.3*f
7.97-8.14 pH
Ca 410-425
Alk 2.5-3 dKH
Amm. 0
Nitrite 0
Nitrate <5

 

[Wrench]

The best photo I can get at the moment.

 

[killingseed]

a lot of differnt things can cause them to receed, not enough flow, too much flow though keep two moded mj in my tank and only putting the the path of the power head is too much other then that they love to have the water flow wave them around some. not keeping your salinity in check can make them close up.
have critters like a sally or Emerald may be picking at them or even fish , clown goby, angels or hippo.

your ca seems a little high but that depands on what your kepping in your tank. i dont maintain my ca too much. i dont have any lps' or sps just zoa's.

you could frag some of the bad ones off and QT them and see how they do out side you tank or in someone else tank.

 

[650-IS350]

whats your salinity ?

 

[mfinn]

Did you checkout this thread?

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1154238

 

[Wrench]

Salinity is at 1.025. I just verified the accuracy of my refractometer with my swing arm and a friends refractometer. Calcium at the moment is at 420.

This colony has been in this spot for two months now and I haven't changed anything in terms of flow or light.

mfinn, I'm reading that thread right now.

Right now I'm leaning towards some kind of fungus or bacteria. Not sure which yet. I'm having a hard time finding quality information on either subject.

Thanks.

 

[InADream]

I am hoping that your ALK is a typo and is not really 2.5 - 3 dkh should that read meg/L... Next what kind of swings do you have... i.e. temp, ph, alk, and salinity... Your parameters look good just maybe your parms swing a lot...

Dream

 

[Wrench]

Yes, that was a typo. The measurement is in meq/L.

Temp swings between 79.2 and 81.3 according to my ACJR.
pH swing is from 7.9-8.2.
Alk drops from 3 meq/L to 2.5 over two or three days.
Salinity stays constant.