Why am I getting this sudden RTN?

[gobble]

Couple year established tank that has been a migration from smaller tanks dating back over 5 years. I've had some of these corals for a long time.

All the sudden this week over about 2 days time one of my big acros goes completely white. Then the coral behind it goes the next day. The nearest one is starting to show signs so I just fragged it up. Here is a video. ( I had just cleaned the glass so the water is a little cloudy)



I had this happen once before and noticed my calcium was low (in the 200's) and it seemed to stop when I brought it back up. I noticed again this week my calcium had dropped to about 300 and I've brought it up again, but the RTN doesn't seem to have stopped. I use a calcium reactor and match alk to 8.5 with an Alkatronic. I always think calcium should follow but I think doing water changes with an amped up salt slowly brings calcium down. All other parameters are good, although I'd like to bring nitrate and phosphate down a bit.

Just reading about black bugs, I dipped the coral that seems to be going and nothing came off except the little star thing in the second picture. I did notice this white stuff under magnifying glasses though. It almost looks like a salt like consistency substance on the coral skin.

The only thing I've added recently is a UV sterilizer. No new corals for several months and they all come from Battle Corals, so not worried about any recently added pests.

Anyone have any ideas?

 

[Uncle99]

If CA is going low like that, Alk may have dropped with it, that could blow out some sensitive pieces.

Sometimes they just go “poof”.

AKA polyp bailout…

 

[Uncle99]

I don’t see any tiny “white” bite marks in the close up pick so it was not munched on.

 

[gobble]

Alk was fine. I've been adding salt with high alk and normal calcium so calcium slowly falls.

 

[jeffchapok]

Have you checked your temperature? I had a heater mishap and the temp rose about 6 degrees overnight. My staghorn bleached completely white within days.

 

[DivingTheWorld]

Do you measure Alk with anything other than your Alkatronic? I have one and they’re not foolproof. Sometimes they get out of whack so I still cross reference with my Hanna.

 

[gobble]

It’s fluctuated between 78 and 82, but I just added fans to keep it down once temp hits 78.2

 

[gobble]

All is 7.8 -8.8 between Hanna and Alkatronic

 

[vetteguy53081]

Check very carefully and with magnifier or phone camera expanded for any bugs or flatworms.
Other causes:
rise in alk
rise in CA
rise in temperature
lights too bright
rise in nitrate
high salinity

Somehow, zooxanthellae is affected and not producing. High light and current often contributors

 

[gobble]

I would say alk has been very steady. Calcium has slowly fallen to around 300 but I just brought it back up to 425 with calcium chloride. Temp has fluctuated 78-82 with the warmer weather. Lights have been the same for 2 years. Nitrate around 4 ppm and phosphate .16. I'd like to bring those last two down because I have some red slime and red hair algae. I have like a 4 stage RODI with cation/anion/and both mixed bed after that, so I think the input water is pretty good.

It's odd because when a coral starts to go it's entirely gone in a day.

 

[ScottB]

Odd that a calcium reactor is not keeping up on calcium. Makes me wonder of the CaRx is operating correctly. No chance it is dumping a bunch of CO2 into the water & room, correct? pH level nominal?

Is the tissue coming off or just going white?

Acros can be like this... seemingly fine and then poof. One thing about a doser I like is how easy it is to know that consumption is falling; that is my first sign something is "off". That and lack of PE. I don't run an Alkatronic, but does it inform you of declining consumption in some way? Dosing logs and such?

You mention hair algae and cyano... using any Fluconazole, Vibrant or Chemiclean? If so, my opinion is formed.

 

[gobble]

The calcium reactor is doing its job. I just think that as I do water changes with a high alkalinity salt the calcium reactor doesn’t need to dose as much to maintain the alkalinity so the calcium slowly falls.

The coral is just turning white. I don’t see any tissue falling off.

my Alkatronic tests every 6 hours so I have a graph of alkalinity usage. It looks normal.

I did dose some Vibrant probably a little over a week ago, just the recommended dose on the bottle. I have not used that in quite some time. Maybe I have my source?

 

[ScottB]

The calcium reactor is doing its job. I just think that as I do water changes with a high alkalinity salt the calcium reactor doesn’t need to dose as much to maintain the alkalinity so the calcium slowly falls.

The coral is just turning white. I don’t see any tissue falling off.

my Alkatronic tests every 6 hours so I have a graph of alkalinity usage. It looks normal.

I did dose some Vibrant probably a little over a week ago, just the recommended dose on the bottle. I have not used that in quite some time. Maybe I have my source?

There are certainly some stick keepers around here that swear the stuff can do evil things. I've run a treatment course of Vibrant on other's tanks a handful of times and it was fine each time. But I've read multiple stories and seen pictures of white-outs.

Same with fluconazole. Used it a dozen times but once it completely decimated and SPS tank in 2 days. Eleven other times all went well.

I believe these SPS crashes are a secondary effect. Perhaps:
Vibrant/fluc damages the cell walls of some algae/fungi/paly that occasionally inhabits some of of our tanks. Something toxic then gets released into the water. It is just a theory. It is not something an ICP picked up for me.

OR the bacteria balance in the tank gets shifted around by the additives, Acropora are dependent upon certain bacteria for their consumption of phosphates.

So I have to answer with a definite "maybe" unless you can think of other potential shifts over the last 2-4 weeks. Acros can be stressing over time and we just don't see it until they totally give out.

I would get a doser running to keep Ca in range.

 

[JPergamo]

I havent used vibrant in years but I would absolutely say you may have found your source if it was added a week ago and now you are running into problems. I'd do a decent sized water change and monitor. Hope you can slow and stop the losses im sorry to hear this.