Monthlies dying? Infection? Or bleaching?

[nickng]

Hi, I recently had a large Montipora started developing a small white spot from the middle and in about a week it became much larger. None of the edges are bleaching and looked healthy. So far all other acros and eupyphilia looks good. Alk steady at 8.3 to 8.5 auto tested every 6 hours . Phos 0.1 ppm nitrates 11ppm. Mg 1380 Ca 410. 1 gallon WC every night
I had the monipora for 2+ years.
Temperature bounces around 76 to 77 daily.
Lights at 38% intensity AB+ from 9am to 7pm 30 mins ramp up and down

FYI tank is 1 year old with 130 gallons actual water volume accounting for volume displaced by rock and equipment.

1st and 2nd picture 3 months ago.
3rd picture earlier this week ~ 8 to 10 days ago.
4th picture , broke off close to half of the coral to stop the spread.. the rest of the white skeleton is encrusted solidly on rock hard to even chisel off.

 

[Catawba_Valley_Reef]

Have you checked for pests? In particular montipora eating nudis.

They will hang out underneath the coral and then feed on it at night. They generally start on the edge and work their way in.

 

[nickng]

Have you checked for pests? In particular montipora eating nudis.

They will hang out underneath the coral and then feed on it at night. They generally start on the edge and work their way in.

It started with a small hole in center of coral not the edges. Don’t see any pest.

 

[Catawba_Valley_Reef]

It started with a small hole in center of coral not the edges. Don’t see any pest.

Ok, another thing I would check is your potassium levels. I’ve had monti caps turn almost a greyish color when the potassium levels got low in my tank.

 

[nickng]

Ok, another thing I would check is your potassium levels. I’ve had monti caps turn almost a greyish color when the potassium levels got low in my tank.

Maybe but I do dose a bit of trace elements. Will check. Thanks

 

[vetteguy53081]

Hi, I recently had a large Montipora started developing a small white spot from the middle and in about a week it became much larger. None of the edges are bleaching and looked healthy. So far all other acros and eupyphilia looks good. Alk steady at 8.3 to 8.5 auto tested every 6 hours . Phos 0.1 ppm nitrates 11ppm. Mg 1380 Ca 410. 1 gallon WC every night
I had the monipora for 2+ years.
Temperature bounces around 76 to 77 daily.
Lights at 38% intensity AB+ from 9am to 7pm 30 mins ramp up and down

FYI tank is 1 year old with 130 gallons actual water volume accounting for volume displaced by rock and equipment.

1st and 2nd picture 3 months ago.
3rd picture earlier this week ~ 8 to 10 days ago.
4th picture , broke off close to half of the coral to stop the spread.. the rest of the white skeleton is encrusted solidly on rock hard to even chisel off.

Assure alk isnt high and/or calcium low,
Other causes will be -
- High phosphate levels up to 5 ppm
- Change in water flow
- Addition of sand
- Changes in brand of salt
- Bad test kits giving faulty results
- Levels of minor elements such as Iodine, Potassium, Strontium
- Light intensity
- - Changes in water flow
- Addition of new corals

Dont go off others' readings and why I dont post mine as every tank has different demands

 

[nickng]

Update… found out it’s montipora eating nudibranch. These look like Berghia Nudibranch but much much smaller ie about 2mm to 5mm in size.
1st time I did a coral-RX dip for recommended 5 to 10 mins I didn’t see any pest.
The second time I left a piece of montipora for much longer ie ~ 30mins and twice recommended dosage. After about 20 mins I saw a couple of the nudibranch appear from a fold or maybe a large pore.
Mystery solved

 

[Catawba_Valley_Reef]

Yup, that’s what it looked like when I originally posted. These are a pain in the butt. If you only have one monti I would throw it away and let the rest of the nudis die off.

 

[nickng]

Yup, that’s what it looked like when I originally posted. These are a pain in the butt. If you only have one monti I would throw it away and let the rest of the nudis die off.

Unfortunately I have 2 large monti’s encrusted on rocks and plating out. I broke of a few pieces to try to save some frags to regrow them. Also have a bubblegum digitata that I dipped in case there are nudis on them too