Help with stn/ bleaching of millies

[alazo1]

hello all,
I'm having a problem with my millies. They seem to be bleaching or stn'ng where the branches intersect. This is only happening on top of the corals where the light hits. I do not see anything on the underside. It's hard to tell but it does look like there are polyps on the white / bare spots but it looks like it may be getting worse. It is happening on two of the pink millies and a green one.

I do not see this problem on any of the other acros I have but I'm afraid that it may spread to others.

Some tank info:
40 breeder sps running about 2 years. Corals are healthy and growing.
I play around with dosing. I started nopox some time ago and nitrates got really low so started dosing some nitrate to bring it up to about 2ppm. Stopped the nitrate and dosing .2ml nopox daily.
I also occasionally dose Red Sea Colors (iodine, trace, pottasium, iron).
Salt was HW marinemix reef and recently started Red Sea Blue bucket (one water change). The problem was happening before the switch.

Lighting - Tek t5 6x39 (I changed an ati blue plus for an old aquablue special a few months ago). Not sure how old the bulb is but it came with the used tek light. Really I'm not sure if the problem started on the changeout. I have used the same bulb in the past though with no apparent problems.
Current bulbs, all ati (4 blue plus, one coral plus, one aquablue special).

small protein skimmer
Pottasium around 400
Nitrate 2ppm
Phosphate around .04 - 08
Alk around 7dkh
Calcium around 420ppm

Any ideas?. Sorry for the long post.

 

[Piper27]

Wow, beautiful tank with very well placed coral and color! Props! I would like to see more about your tank for sure.
I can't think of anything that would cause damage like that other than aefw but I assume you have checked for them. They are very slick at going unnoticed though. The damage looks like burned spots though, and I can't think of one thing that would cause burn in that area. Have you double checked all the basics? Salinity, tds, power heads working correctly? Document the progress of the damage if it continues.

 

[alazo1]

Thanks for the complements Piper. I will have to give more info on the tank when I get a chance.

Wow, I will have to do some research on aefw but from the little I know, it is not a good thing. I did treat a few corals for red bugs with a bayer dip that seems to have solved the problem (at least for now). I do not see red bugs in the millie but it appears that aefw's would not be visible in white tissue. Will the aefw leave polyps or just eat the whole tissue of the section?. I can remove the coral in the picture to inspect and dip in bayer to see if that helps.

I just replaced the aquablue special for a newer purple plus that I had in case it's a lighting issue. I think I may cut down on the Red Sea Colors for a while as well.

Albert

 

[codydemmel4]

Thanks for the complements Piper. I will have to give more info on the tank when I get a chance.

Wow, I will have to do some research on aefw but from the little I know, it is not a good thing. I did treat a few corals for red bugs with a bayer dip that seems to have solved the problem (at least for now). I do not see red bugs in the millie but it appears that aefw's would not be visible in white tissue. Will the aefw leave polyps or just eat the whole tissue of the section?. I can remove the coral in the picture to inspect and dip in bayer to see if that helps.

I just replaced the aquablue special for a newer purple plus that I had in case it's a lighting issue. I think I may cut down on the Red Sea Colors for a while as well.

Albert

any update on this? also very nice tank

 

[alazo1]

I've been keeping an eye on it and it seems about the same. However I just looked top down on the rest of the corals. Seems like it is happening with a Paletta blue tip (lightening / bleaching / stn on the intersections). I'm not sure if it's a new issue or that it has been happening since the millie.

I did switch salts about 2 months ago, from HW Marinemix reef to red sea blue bucket. I remember about a month ago I accidentally did a 20 gallon water change with this salt which is about 35%. Total volume is approx. 55 gallon. I have a pump in the sump that removes tank water before a water change. I forgot to turn it off. Good move..LOL.

I have some of the old salt (MarineMix) and may start it back up to see if it reverses the issue.

Any ideas?
thanks,
Albert

 

[codydemmel4]

im thinking and im no SPS expert in any means (your tank is nicer then mine) that since it is only at the intersections that theyre either not getting enough light, flow or both. I have seen this with a lot of my bigger colonies on the sides where it is in the shade it is white and looks like STN but the rest of the coral is doing great and it has been like this for months, seems pretty similar in your case. Would be nice if some of the expert SPS people would chime in.

 

[shingo43]

The could be caused from KH swing, your HW Marinemix reef salt has alkalinity about 9.5 and rea sea blue's KH is about 8 and you did a big water change.