Patchy bleaching on some coral

[Reefs and Geeks]

I've recently noticed that a few of my coral are looking very pale in some sections, but not the whole colony, and not all of the coral in the tank. I'm trying to pinpoint what might be causing it so I can try to reverse it. I tried getting some pictures, but the pale parts aren't showing well in the pictures. I'll add some if I'm able to get any good ones. So far, I've noticed taht

Tank history
* Increased tank temp from 77F to 81F over a few weeks about a month ago. Has been at 81F for maybe 2 weeks. I dropped the temp down to 79 over the last few days and plan on leaving it there for now to see what happens.
* Feeding habbits are the same-2 full shrimp a day and a scoop of pellets
*Alk container ran dry about a week ago, but didn't seem to miss dosing much before I caught it. Alk measured 9, normally kept at 9.6-10.
*lighting dimmed down a few days ago by about 10% as a reaction to the pailing
*nitrates measured 20ppm this morning. I dose vinegar a couple times a day and have not changed dosing. I plan to increase slightly to slowly bring down to 5-10ppm range
*added a couple cups of GAC to a reactor. 2-3 cups for a 300 gallon system

I can't think of anything else that I've done differently. I strongly suspect it's the temp, but I also hear alot of people say 81 is fine. I did calibrate my temp probe with a lab grade thermometer, but plan to double check it to make sure it has not drifted.

 

[Perthegallon]

I have the same issue very similar tank other then the temp change

 

[Perthegallon]

The only way I stopped them from dying I did was two things turned down the lights a lot and started to add a lot more food and hand feeding them

 

[Reefs and Geeks]

Also worth noting, I do dose some aminos as well and have been for 6+ months.

 

[Whasmack]

Are the pale parts in direct or indirect light?

 

[Reefs and Geeks]

Thanks, I will start target feeding them and see if that helps as well. That actually reminds me, I was broadcast feeding reef roids once a week, but stopped when I ran out. I'm still dosing aminos though.

 

[Perthegallon]

Thanks, I will start target feeding them and see if that helps as well. That actually reminds me, I was broadcast feeding reef roids once a week, but stopped when I ran out. I'm still dosing aminos though.

I started to get pellet food for corals and I fed those directly so I could see who was getting and who wasn’t then I started adding an+ daily

 

[Perthegallon]

Ab*

 

[Reefs and Geeks]

Are the pale parts in direct or indirect light?

They are in direct light for most, but did notice fore a green monti cap that there is a spot in the shade. Not sure if it's die off because it's being shaded, or if it's related to the other coral's issue. I even have a setosa that is looking more pale all over, but is located 25" deep in the sandbed.

 

[Reefs and Geeks]

The worst looking one is a turbinaria that is at medium height in the tank. it's maybe 9" diameter, and has a 2" x 2" section that looks quite pale. Not pure white, but very noticeable. The rest of the colony looks normal.

 

[Whasmack]

Oh paling in direct lighting - yes keep your temps down under 80.
Usually paling, from my experience is too much light or too little nutrition (and not necessarily n03 or p04)
Maybe others will chime in, but I’d like to see pictures!

 

[Reefs and Geeks]

Got a few decent pictures last night, though it still looks worse in person than in the pictures. You can see two paling areas on the turbinaria, and one on the red monti cap.

I made an extra dose of aminos last night, and ordered some more coral food.

Thinking I may drop the temp again from 79 to 78 to see if that helps as well.

I was also thinking me puting in fresh GAC might have made the water "too clear" and effectivly made the lights brighter at the coral. I'll leave the lights at 10% less than they were before for now to try to limit the changes I'm doing all at once, but will lower them another 10% if the paling looks any worse.

 

[Whasmack]

Good -
Can you list out as many of your tank parameters as possible?
What lights do you run?

Have you checked for pests? Red bugs?

 

[Reefs and Geeks]

Latest tank parameters, (2 days ago)
Nitrate: 20ppm
Alk: 9.9
Salinity 35 PPT (calibrated refractometer)

I still need to test Phosphate

I run blackbox vipar spectra lights. Been running them since I started this tank about 2 years ago, and haven't changed their settings in as long as I can remember. 4 lights over a 150 gallon display (72"x18"x27") @ 85% blue and 10% white. Lights are on about 12 hours a day.

I haven't checked for pests. Never crossed my mind as I haven't made any additions to my tank in months. Will take a close look this evening to see if I can see anything. Any tips on finding pests? just a very close look at the coral or are there better methods?

Thanks

 

[Whasmack]

Usually when lights out & with a bright flashlight make it easier. Red bugs you just gotta know what you’re looking for (look up pics). They are very small.
How quickly is it spreading?

 

[Reefs and Geeks]

I didn't see anything yesterday, but will look at them tonight with a flashlight. It's not spreading very fast. Been looking pale for a few weeks, but I initially didn't think too much about it untill it got worse. It seems like the size of the pale spot may be spreading very slowly if at all, but has gotten more pale since I've noticed it.

 

[Whasmack]

I’ve had a similar issue with acros and monti’s.
I started dosing Reef Energy A&B and awesome an immediate turnaround in like 3 days. I posted pics before, I’ll see if I can dig them up.
I’ve only had great results with reef energy; not so much with others.

Also, I’ve seen slow recession when carbon dosing. You could halt the aminos & carbon dosing to see if it slows down, but it doesn’t sound like tissue recession.

 

[Flux Capacitor]

I had a monti a few years ago that looked just like your green one. Turned out to be monti eating nudis. Hopefully you don’t have those, but if you do when the lights go out they will come out. They look like little mops crawling around. They hide under the middle of the coral during the day, if you’re able to remove it and check the underside you’d know right away.