ID please

[belgian_waffleman]

Hello,

I have a yellow tang, that's been in my reef tank for about 3 years, doing very well, eating good etc...

now, today I noticed a white spot with brownish edge at one end.:hmm2:
See inserted photo.

Could it be lateral line disease?

my tank parameters are :

ph:8.4
nitrate 0 ppm
KH = 8 dkh
ca =300
sg = 1.025
Temp = 79.1 degF

My calcium level is usually around 400ppm, but I ran out of supplement last Wednesday. every thing else is very consistent.

Yesterday, I've added a powerhead to the tank (MJ1200)

Any ID would be appreciated, as well as suggestions on how to remedy it of course.

Thanks in advance

Waffleman

 

[Percula9]

From the picture it doesn't look like much. I don't think it is necessary to treat at this time. If it seems to get worse then take action. Right now just observe. Definitely not HLLE.