is this coral gone? Or not?

[WhiteTang]

Hi!

I recently added 3 SPS frags in my system. Its a 16g nano about 8 month old.

Params are:
Salinity: 1.024,5
temp: 24,5 °C
dKH: 8
Ca:380
Mg: 1400
ammonia/nitrites/nitrates: 0

I have mostly corals and only two small fish (2,5 inch each) which I feed twice a day but very lightly. Almost no food reaches the bottom.

All my LPS are doing extremely well. 2 of the SPS look just like the day I bought them except the one on the pic.
Its a Stylophora milka. This was a freshly cut frag from a colony and it had the all over "fuzzy" look from its polyps. Now the polyps are almost gone and only a few are left. Even these don't extend as they should.

I attaching a pic so you can see the state it is in now.
Do you think it will recover? Or is this coral ready to go?

 

[shesacharmer]

I'd leave it as long as you see any polyps at all. It could recover.

 

[DDon]

Not gone yet. It looks pretty rough and seems to have experienced some rtn/stn. I believe you posted in the sps forum a few days ago and it looks like it has receded a little more since then. I usually frag off what I can when I experience rtn but since it is a small piece I wouldn't do that in this case. There are still polyps so there is still hope. Stylophora are fairly hardy (for sps) so I would leave it be and see what happens. Keep parameters stable. Ca is slightly low so maybe slowly bump it up.

 

[tmz]

Have you tried lower light?

 

[WhiteTang]

Not gone yet. It looks pretty rough and seems to have experienced some rtn/stn. I believe you posted in the sps forum a few days ago and it looks like it has receded a little more since then. I usually frag off what I can when I experience rtn but since it is a small piece I wouldn't do that in this case. There are still polyps so there is still hope. Stylophora are fairly hardy (for sps) so I would leave it be and see what happens. Keep parameters stable. Ca is slightly low so maybe slowly bump it up.

Hey DDon, yes I did post in the SPS forum a few days ago and i has indeed receded since then. The piece is quite small so fagging would be pretty hard without killing it completely. Ca is on the low side but not that low to cause damage I suppose. no?

 

[WhiteTang]

Have you tried lower light?

No I haven't tried lower light. I don't really have a super strong light to start with but I think it is sufficient to keep SPS. At least the other two that I have seem to like it.
I will try moving it lower since with now this far is at the highest point it could be in my tank. Although wouldn't the top polyps be the first to "suffer" the damage?
If you look at the picture this frag has lost its polyps from the bottom up not the other way around.
But since these are my first SPS I don't really know that much.

 

[tmz]

380 calcium won't be a problem.but could be a little higher.400 to 450 works well. I run near 500ppm. The polyops seem closed even on top;hard to say from the picture. .Sounds like the light you have is moderate,though. Heavy flow? What about nitrate and phosphate. Any sponge or detritus buildup under it?

 

[DDon]

Hey DDon, yes I did post in the SPS forum a few days ago and i has indeed receded since then. The piece is quite small so fagging would be pretty hard without killing it completely. Ca is on the low side but not that low to cause damage I suppose. no?

As TMZ said ca of 380 isn't a problem; I was just making a general observation.
I'm also curious about flow and this coral's proximity to any powerheads.

 

[WhiteTang]

380 calcium won't be a problem.but could be a little higher.400 to 450 works well. I run near 500ppm. The polyops seem closed even on top;hard to say from the picture. .Sounds like the light you have is moderate,though. Heavy flow? What about nitrate and phosphate. Any sponge or detritus buildup under it?

The polyps are indeed somewhat closed. The light is a Giesemann PULZAR HO 28W full spectrum LED. Unfortunately I don't have par readings for the LED no matter how hard I tried. I even contacted the manufacturer about it and did not get a clear response.
For flow I have an VorTech MP10 which runs at about 40% max (reef crest setting) and is not shooting directly on any coral.
Nitrates are 0. I have no idea what the phosphates are cause I have no kit to measure it. But I should mention that I have since day 1 used only RO/DI water and have been using seachem phosguard. My guess is, I probably don't have any phosphates. The coral in question is sitting at the highest spot in my rock work. There is about 4 to 5 inch water above it and the light is sitting about 2 inches from the water surface.
There is no sponge nor detritus buildup under the coral.

 

[tmz]

It's possible nitrogen or phosphate are deficient with a zero NO3 reading and phosguard in use. I don't have experience with leds only and sps but it may be light intensity combined with a nutrient deficiency. I was also thinking some toxin from deteritus buildup or a sponge or something. Can't think of anything else if your measures are accurate. Hope you can save it.