SPS STNing from the center? (w/ pics)

[ryanuuy]

Hi guys! I have a 155g DT with 80g sump. I run 5 AI sol blues, ATB deluxe 10.5 and 4 MP40s in the DT for flow. I also use BP in a reef octo reactor and i have a chiller to keep the temp steady at 25degC.

Its a mixed reef and i keep LPS, SPS, and zoas. For some strange reason, the milleporas(i have 3 colonies) and one of my acros have started to STN or bleach out from the center outward. The bases are totally fine its really just the center part. These SPS have been with me for at least a year and i have grown them out from small frags so i dont really understand what happened. The other SPS in the tank all seem to be doing fine. The LPS and zoas are also doing ok.

Salinity is stable at 1.025. P04 is 0. Nitrate, nitrite, ammonia all 0. Cal is stable at 450. Alk in between 7-8. Im quite sure of these numbers since i test quite regularly.

I also use a bit of zeo but not the whole system. I only use coral snow, pohls xtra, and amino acids to help the corals grow faster.

Please help!

As you can see with this mille, the tips are all ok. Its just the center which has a problem.

Its the same case with this acro as well.

 

[Logzor]

I experienced this exact issue. It turned out I had a bad bottle of refractometer calibration fluid as well as a bad temp probe.

I brought a lab grade probe on Amazon for $20. Found out my temp was 71 degrees. I got new calibration fluid, my salinity was over 1.030.

It took a long time but this problem started at the center, just like yours, with the remainder of the coral looking super-healthy. Eventually it almost killed entire colonies but I fixed the problem just in time.

Another potential issue is that there is not enough flow.

 

[ryanuuy]

Thanks for replying quickly logzor!

Hmm, actually i have 2 refractometers and both have the same reading at 1.025. I'll lower it at bit to 1.024 and hope that helps a bit. As for temp, its regulated by my chiller and im pretty sure its around 25deg-26degC.

Is there anything else you did that helped fix it like more water changes? Adding more activated carbon? Lessening BP? etc?

 

[Logzor]

Nope I just corrected the temp and salinity. It's been a slow recovery but my corals are finally able to take off in growth again.

Still, I definitely recommend getting a nice thermometer from Amazon as well as new Sybon calibration solution.

If they're both reading 1.025, what's that based on? They have to be calibrated with a standard solution. Both having the same reading only means they were both calibrated the same. It definitely does not necessarily mean your water is actually 1.025.

I was calibrating my refractometer and pinpoint monitor with the same bad calibration solution...

You see where I am getting?

 

[NVfishman]

I have had a lot of acros the biggest issue is the alk swings, salinity , and temp consistency,

Looks like a large maricultured or wild piece the Key to them is flow especialy if it is stn in the center.

I would get the power heads creating alot of flow then double it there should be a ton of water movement alot more then reccomended.

I have talked to a few coral importers on the same issue

pics are hard to see dead area.

I would also lok for AEFW as the base is the first thing to go

 

[ryanuuy]

I already double checked actually and im pretty sure there arent any AEFW or red bugs. I removed them and looked for any sign of damage uneathe the colony that look like bite marks and i couldnt find anby.

Alright ill be upping flow and ill check the alk more often as well to make sure. Is there anything else?