Strange repeated melting issue w large sps at base

[Biff0rz]

I have a strange issue and I'm not clear of the cause (shocker, sps). I've had no swings, no changes, and have added zero coral or fish for 6+mo.

Two Icps came back normal (oceamo, ati), maybe low in some areas but not by a lot. (moonshiners)

In October my large, healthy (?), Vivids Confetti, I saw this melting effect near the base of the acro. It lost some color around the base (not stn or rtn) but the base did lose color and started getting algea. Some of the colored areas w polyps had this melting effect.

So, I cut it above the bad area and it's healing up fine. I chalked it up to 'well, that's sps for you'

Ffwd to last week. Poto side chick, again healthy size, and it starts happening right in the center. So I cut it. But then it spread a little. More melting effect.

So, I end up chopping it up. But now this is the second established acro doing this and I have zero leads to solving it.

Anyone experience similar? Thoughts?

 

[Rocks reef]

@ReefSquad

 

[Gumbies R Us]

What are your parameters?

Lighting they are getting?

What about flow?

Any recent changes to your tank?

Wondering if it could be a case of RTN/STN

 

[SeaDweller]

it's probably from detritus settling on it, and then the tissue dies, then you get those bald/slimy spots that has to grow back. happens to a few of mine, have to baste the colonies every couple of days or so.

 

[GHOSTLY]

I just had this issue last night from the base/underside. The acro had low flow and low lighting, fragged whatever i could to save it. I noticed every case of rtn/stn ive had has been in shaded areas or low flow areas. I use superglue to patch the tissue up and out of 7 pieces its worked for 4

 

[Biff0rz]

What are your parameters?

Lighting they are getting?

What about flow?

Any recent changes to your tank?

Wondering if it could be a case of RTN/STN

parameters? which ones? lol

Tank is 5yrs old-
alk 8.5, no3 10, po4 0.11, ca 440, mg 1345, sg 35ppt, 78*
doing moonshiners, regular ICP's

Lighting -- 5th long tank, 2x photon v2+ 50's @ 80%, 5hrs white period, 10hrs photperiod, 2x or3 sky blue light bars -- top acro's @ 450 par, bottom @ 200 par
First acro- 300 par (vivids confetti)
Second acro- 250 par (poto side chick)

Flow- tons! -- 2x mp60's @ 80-90%, pulse, async. 2x Jaebo SOW-20's @ 70%, pulse, async. 2x no-name jaebo (smaller pumps) to create turbulance @ 80%

No recent changes

Both are rtn/stn --
vivids - I cut it and remounted to a plate. The colony has re-based and recovered. The remaining base did end up rtn'ing
side chick - i cut some large chunks off. One was closer to the 'melt' point and has rtn'd. The other large chunks have re-based. The base that was left rtn'd

 

[Biff0rz]

it's probably from detritus settling on it, and then the tissue dies, then you get those bald/slimy spots that has to grow back. happens to a few of mine, have to baste the colonies every couple of days or so.

I blow my acro's off frequently, rarely do they have much detritus (I have a lot of flow). But if there is some, it'd not there for long. With these two, it's possible the side chick had some. The vivids, there was no way it had any on it.

 

[Biff0rz]

I just had this issue last night from the base/underside. The acro had low flow and low lighting, fragged whatever i could to save it. I noticed every case of rtn/stn ive had has been in shaded areas or low flow areas. I use superglue to patch the tissue up and out of 7 pieces its worked for 4

So, for the vivids, I would say the brown/stn did start in a lower light area. It did have good flow though.

For the side chick, the stn started right in the middle of the colony, adequate flow and light.
This is what it looked like in the middle before I cut it out-

you can see the middle part of the colony (this was the OG frag I bought before it based/grew branches) is where the melting started. Nothing settled there and as I said, lots of flow/light. You can see a single branch started to s/rtn -- I call it stn because before I snapped this pic, it was looking not great there for about 5 days, it looked melted/polyps retracted. But the skin was still in tact.

the picture in the original post is after I cut it out, which is this one (again)