Any thoughts on the recovery @Jay Hemdal
I did develop another theory. Just now!! October of 2019 I was battling high aluminum, 363 on the ICP test. I couldn't get it to come down and starting in July of this year I upped my normal 15% weekly water changes to 25% for 6 weeks straight and replaced the ROX with Brightwell Aquatics Purigen aggressively to try and bring down the aluminum. By aggressively I mean using more than needed and replacing every week. I was so focused on reducing the high aluminum I didn't consider any possible negative affects from my plan. I did another ICP test in September and the aluminum dropped from 363 to 28. That would put the timeline to mid August or about 3 weeks before I noticed his slime coat turning white. If you haven't used Purigen before it very messy and impossible to rinse until the water runs clear. Now that I think about it that seems to be text book for what not to use as a carbon source with tangs. As you said black tangs are sensitive. I'm starting to suspect the aggressive use of Purigen or Purigen / ozone combo. Who knows? Anecdotal I know. No other fish or coral colonies seemed affected. If anything my colonies had a positive response. I do have a yellow eye kole tang that I've had for years that hasn't been affected but, I think they are a hardier species of tang.
I was a bit too busy this afternoon for a pic. I will try to post one tomorrow. Thanks to everyone for their response.
I went back and checked my records and located the receipt when I bought it, January 6, 2019. After it went through my normal 6 week QT it has been in the DT while running ROX. I've never seemed to have a problem running ROX. It could have been the combination of ROX and ozone at the higher level I was running it. The fish improved after I stopped ROX and started the ozone back up at a reduced rate. My water is still crystal clear running the ozone without the ROX.Good news! I’ve not had any reports of that carbon causing issues, but black tangs are so sensitive, who knows? Thinking back on the timeline though- did this start before or after you stopped the ozone? You said the fish started to improve after you started it back up? I see some weird things here when our ozone goes down- not lesions like that, but cloudy water due to bacteria, etc.
Jay
I did develop another theory. Just now!! October of 2019 I was battling high aluminum, 363 on the ICP test. I couldn't get it to come down and starting in July of this year I upped my normal 15% weekly water changes to 25% for 6 weeks straight and replaced the ROX with Brightwell Aquatics Purigen aggressively to try and bring down the aluminum. By aggressively I mean using more than needed and replacing every week. I was so focused on reducing the high aluminum I didn't consider any possible negative affects from my plan. I did another ICP test in September and the aluminum dropped from 363 to 28. That would put the timeline to mid August or about 3 weeks before I noticed his slime coat turning white. If you haven't used Purigen before it very messy and impossible to rinse until the water runs clear. Now that I think about it that seems to be text book for what not to use as a carbon source with tangs. As you said black tangs are sensitive. I'm starting to suspect the aggressive use of Purigen or Purigen / ozone combo. Who knows? Anecdotal I know. No other fish or coral colonies seemed affected. If anything my colonies had a positive response. I do have a yellow eye kole tang that I've had for years that hasn't been affected but, I think they are a hardier species of tang.
I was a bit too busy this afternoon for a pic. I will try to post one tomorrow. Thanks to everyone for their response.