SPS deteriorating - unknown reason

[thefuz]

Hello, all.

I've recently been experiencing sporadic cases of RTN to a few SPS in my 90 gallon mixed reef. Most notably my red monti cap just started accelerated tissue loss. Parameters are stable at:

Alk: 147 (Hanna)
Ca: 400 (Salifert)
Mag: 1540 (Salifert)
NO3: can't measure (dip strip / Salifert)
PO4: 0.028 (9PPB via Hanna low range meter)
Temp: 76.5 - 78.5

This seems isolated to montipora but both plating and encrusting. Attached photos show the damage - some of the more jagged spots are where I've tried to snap off the bad parts ahead of the crash.

I'm not sure what else to look for at this point since some of the more prickly SPS is doing quite well (if you can see the good PE and color in the second shot). LPS, clams, zoa, blastos, etc. are all unaffected.

 

[fishguy597]

Are you sure you don't have nudi's?

 

[thefuz]

I'll take a closer look but I don't think so - unless they're nearly microscopic.

 

[BrentH]

There easy to spot look on the underside they stay out of the light white or after lights go out check for them

 

[Tweaked]

Seems to rapid for nudis IMO. Alk swings, warfare, or foreign substance in the column possibly.

 

[trueblackpercula]

Could it be flow? Or coral warfair ? I don't think it's alk because the other Sps look amazing. Also check for crabs that may be picking on it at night.

 

[thefuz]

Checked for critters last night. The only thing I see are tons of amphipods all over and those are likely only there to clean up the dead and dying material. I siphoned material off the top in the affected areas and didn't notice anything suspicious, unfortunately.

It is pretty close to a hammer coral but they've been neighbors for nearly 2 years. The hammer growth has been accelerating lately though. Perhaps that was a catalyst for the crash of this particular coral. I don't know why that would be making other monti's recede though - and not all monti's. I have several others that look just fine.

Grr!!!

 

[kjamaya]

I've had this happen to me before and it was because I was manually dosing my tank. I use the salifert powder for alk and was just pouring it into my tank instead of overflow. I believe the the alk was settling on my montis and killing certain areas. I started pouring the solution into my overflow and haven't had a problem since.

 

[thefuz]

A good thing to check but shouldn't be a problem in my case. I dose 2-part with a pair of BRS dosers periodically throughout the day and Alk is stable (it may fluctuate a ppm or two over a few days).

 

[Peter Eichler]

Monti caps are one that I struggled with color and health wise for a long time until I bumped my nitrates to detectable levels. Something to consider...

 

[nogascans]

Second the nitrate levels (up). I recently made an error in carbon dosing and dropped my Nitrates to near 0, phosphates near the same. Only SPS to show issue were Montipora (bleaching areas) and Birdsnest (thinning, burnt tips). Alk was in the 10-11 range.

I brought them back by bringing Nitrates to 3-5 and Alk to 9.

Sincerely,

David

 

[thefuz]

Hrmm... it's possible my algae scrubber and chaeto are too prolific. Perhaps I'll try reducing both gradually and see if that helps. The Monti is nearly toast at this point though.