sps Help, bug or bacterial?

[kevinl]

Have seen underside slowly going for 6 months or so.
Have had 2 downward trends in color of several acros & most monti's in past 6 months.
ICP nothing stands out, no heavy metals. (if I could connect to their site I would post numbers) recent test 1 month ago.
360 total water volume, 120 sps, 90 lps & 120 long, half zoa other half fudge & 75 sump.
System running since March 2013, with a couple upgrades
I test regulars (KH, Po4) often, usually 4 times a week.
KH 7.3 - tank has looked its best last year when I maintained 6.5 to 6.8
Ca 440
Mg 1440
Ph 7.9 to 8.1
Po4 0.05
No3 10 to 15
Test kits Sailfert & Hanna
I have 2 reactors, one runs half to 1 cup of BRS high capacity gfo when needed. I keep close eye on this number.
The other one I use for BRS Rox carbon when needed as well.
Lighting is 2 Radion gen 3 xr 30 pro, Reefbrite xho 48" & 4 360w tuna blue Kessils (120 sps tank) 9am to 9pm custom settings 1 1/2 hour ramp up & 3 hour ramp down.
Lights 10" off water level.
I watch the nutrients numbers often cause I feed heavy, one frozen feeding, 4 auto feedings (my own mixture of freeze dried products from Brineshrimp Direct) and one feeding of russ"s HPD
Fish load, medium stock level, 13 fish.
Here is a shot of my green slimer, its now has what looks like gray/blue tips. I shined a flash light on the underside for picture.
Whats green looks good, but various areas are bleaching out, there are several patchs through out.
even the digi to left has a side going bare.
What do you think? Bug, bacteria or something else.

 

[LobsterOfJustice]

Infections are rare, move faster than that, and are not restricted to the underside of the coral.

To me this looks more like a shading issue due to using only LED lighting. I think you would see improvement if you added some T5 tubes.

 

[LobsterOfJustice]

Hold it - upon closer inspection I see hydroids growing on the dead areas on the underside of the slimer.

I actually experienced the same thing. The hydroids do not directly settle/expand on live tissue, but they are on tiny stalks and they will kill the tissue a few mm at a time and slowly work their way up. I saw this in my own tank. Typically the coral grows about as fast as the hydroids spread so not an overall threat but makes for ugly colonies.

There is a big thread on fenbendazole to kill hydroids. I treated my tank several times and they disappeared but came back. Been crossing my fingers and haven’t seen them in a while but it might just be a semi annual treatment to keep them at bay.

FYI - heavy feedings of small foods also makes these guys happy. Consider cutting back the particulate foods if you don’t have filter feeders that you are specifically trying to feed and just feeding the fish larger particles.

 

[kevinl]

Thank you sir!
I had a suspicion of hydroids, I was looking at the right side of the photo around the middle of the shot and I see little tiny what looks like feather dusters (are those the hydroids?)
Was just talking to a buddy of mine (didn't have photo with me) he brought up white line disease or bacteria.
When I was processing the photo, which was 10 pictures stacked together in photoshop that white line stuck out to me a lot! however at the time I thought it was from the photo stacking in PS. So I just get back home and to the naked eye that white line is clearly seen, however it could just be white due to the attack of what ever is causing it to receed.
I do believe I have other issues going on as well, or would the attack of hydroids cause color change in the coral? The slimer has what looks like purple or bluish tips now (that started 2 weeks ago)
Thank you for your help!

 

[JaimeAdams]

#reefsquad

 

[LobsterOfJustice]

Yes the hydroids are what look like tiny feather dusters.

The white line just looks like dieoff that could be caused by hydroids attached to the old dead skeleton.

I have also dealt with what I believe to be a bacterial disease but it was on montipora. That disease leaves a band of fluorescent tissue as it moves. Not saying all will look like that. But I think something bacterial would move a little faster (not as fast as RTN, but faster than the hydroid progression).

 

[Charlie’s Frags]

I see some vermatid snails (hate those things) that could be irritating it as well. I’ve seen my acros grow right over them, grow around them, retreat from them (like yours are doing) or stn and die.