All monti's RTN'ing, everything else fine

[lowman31]

All my sps are doing fine...my Monti's are bleaching or RTN'ing or something. It started with one Monticello that was on the bottom of my aquarium. Then it happened to another one on the bottom. Then it happened to one that was mid way up. It started as a 1 cm white spot and quickly advanced killing the coral after a day or so. The last coral to go was a hardy coral Thad was about a foot in diameter. I lost half of it over the last two days.

Alk 8-9 dkh
Salinity 1.025 refractometer
Ca 450-500
Mg 1800
Phos ?
Nitrates 1-2 ppm

I have a 400 gallon system with 3x 400 watt MH lights with t5 actinic

I am wondering what could be causing this. I can't find any bugs and am worried I have a bacteria. Any feedback would be appreciated.

 

[Reef264]

Your Magnesium is 450-500ppm too high.Your Corals could be starving for Nutients, do you feed your SPS?

-Ray

 

[CUZ]

nudi's??

 

[Finland]

Recent replacement of lights? I recently replaced mine and managed to bleach out all of the encrusting mon tis. They are recovering, but lessoned learned on new light acclimation. Just an idea. Also, your mag is too high. I like to keep mine in the 1350-1450 range.

 

[Steve175]

The Mg+ is high, but not the problem.

I would pull out the dead/dying monti and look underneath for evidence of nudi's

 

[NVfishman]

I had nudis 3 years ago if the coral is slowly dieing look under coral at nite,

I have alost had what u describe where montis start dieing quick turning white with somtimes a grey slime.

I dont know what causes it but typically it will wipe out all or most of the colony, what I have done when this has happend it chop the dieing part off oth colony and in time it will heal up and be fine doesnt work 100% of time but I have had good luck doing this

 

[lowman31]

Thank you for the replies. My montis are dying fast. NVfishman, I am having a grey brownish slime and I removed all the dying parts. I searched my purple monti very hard for anything that looked like a bug and found nothing. I think I may have gotten through this but I haven't done anything but removed the bad parts of monti. I have an 8 x 8 piece of purple monti left with one dine size white spot that has not grown over the past 48 hours.

I do feed my corals as well as feed my fish heavy. I have a soho that eats a lot too.

Thanks again everyone. Let me know if you have any more ideas.