Corals slowly bleaching

[funkejj]

So two weeks ago the tank was great everything had good color and no issues with any of our SPS. The first thing was our green hydnophora starting to lose tissue. I thought maybe it had to much flow and moved the powerhead being it was just one of the colony's in the tank. Over the course of the next week I noticed that both colony's and the frags of hydnophora I had were losing tissue and bleaching out. Sunday night I saw one of my acros has a small bleached spot on it say 3 mm across. Today lights come on I see the spot has increased to 8 mm or so in diameter and looking at other corals I am seeing some bleaching around the edges at the bottom of them where they are encrusting. As a whole the corals still have good color except the areas where they are bleaching at. There has been no coral additions to the tank in 6 weeks ish. I added a purple tang 4 weeks ago but has never touched a coral one.

My parameters (tested today) are as follows

Ph 8.1
Temp 80.5
Salinity 1.026
Nitrates 5
Phosphates .01 Hanna
Alk 9.24
Calcium 460

I run GFO (have ran it for 18 months) & GAC (started running it 4 weeks ago turned it off when this started).

I have LED's for light, oceanic salt same salt I have used for 2 years, and vortech power heads.

I am at a loss for a cause and any help would be great.

 

[gon08]

If the only thing you have done different is the GAC then I would think that was it. If the addition of new GAC cleared up your water it can cause the corals to bleach. It's gonna be a while for them to recover.

 

[Donkeykong]

What LED's are you using and what are the dimensions of your tank. From all my reading bleaching happens rather quickly not a slow progression. If it is bleaching then the tissue is still there just void of any color, can you still see tissue or is it just skeleton? If it is skeleton I would search STN.

 

[Logzor]

Double check that your temperature is correct, I had a similar issue due to a broken temp probe, I was actually running 6 degrees less than I thought I was.

Same goes with alkalinity, try another test kit.

I would pull the GFO for now. I rarely see a thread like this were the person isn't running GFO.

No recent change in lighting?

 

[funkejj]

In november we built a retro fit led setup using 3w cree LED's they are running at like 65% have had no issues due to lighting. Have checked the Alk with both Hanna meter and using a Salifert kit both readings were close. The tank is a 180 standard size with the LED's 15 inches above the tank. I am uploading pictures to show the issues I am referring to.

 

[funkejj]

I checked temp again by a second means it is 81 degrees so Temp is ok.

This started 2 weeks ago and has progressed to this.

This was fine 3 days ago

This took a fall to the sand last week put it on the frag rack and just seems to keep bleaching.

Here is the acro frag, one other frag has similar issues as this one

 

[Masterofnonsense]

What brand of GAC? Kent just recently had an issue with heavy metals in their GAC.

 

[funkejj]

I am not sure of brand other than it isn't kent. My lfs refilled me from a big bucket and he refuses to sell any kent product. I was worried about that but from what I have read all corals died quickly I ran it two weeks before noticing issues.

 

[igot2gats]

What is GAC?

 

[Adrnalnrsh]

Granulated Activated Carbon

 

[cichlid9]

that last pic of the acro frag looks like rtn to me

 

[mightymizz]

Definitely looks like there is some tissue necrosis going on. Do you run any carbon dosing such as Zeovit, Vodka, Pellets?

Any swings in your elements lately, such as Alk? Although Alk swings usually show different symptoms, but still good to know.

Something is definitely not right in the water. Did any household sprays, or any other potential substance get into the tank?

I have no idea on LEDs so I can't help you there.

 

[funkejj]

We did add vinegar to our kalk but have been doing that for a while. I do my best to avoid any sprays anywhere near the water not to say my daughter did not put something in the sump. If it was RTN wouldnt it consume the whole frag with in a day vs a spot growing slowly?

 

[Dog boy Dave]

RTN =Rapid tissue Necrosis vs STN = Slow Tissue Necrosis These only describe symptoms of coral stress not a disease or cause. Dont get distracted here. Most of your corals are exptremely hardy pieces. Not sure whats going on but at this point, all you can do is massive water changes and get you cycle working again. Stop the carbon. You might try jump starting your bacteria culture with one of the comercial products available to cycle tanks. I cant speak to the GFO as i have never used it. However i read about these kind of problems in gfo tanks all the time and I have maintained a very sucessful SPS system for about ten years now with out using that product. I have seen old Berlin tanks do what yours is doing in the past. Massive water changes and a bacteria boost helped those tanks recover. Their long term fix involved a remote DSB and increased organic loads but that is a different issue.