Ozone might've killed my Achilles Tang

[mikethefishman]

About 5 months ago I upgraded my 125G system to a 550G system. Re-QT'ed all my fish, corals, and inverts before introducing them into the new system. Lost a Two Spot Bristletooth Tang in the QT process but over 2 dozen other fish made it through QT without any problems. One of them was also an Achilles Tang. This guy was a champ, and everything was great. Then in the last couple months the water clarity went completely into the dumps. It's been running with UV sterilizer ever since the tank got cycled and it was doing pretty good for a couple months. Then out of no where the water just got cloudy and I'm not sure what went wrong. So last week, I got a Ozotech ozone generator because the UV and the carbon media just wasn't cutting it. I've also heard that a big system like mine should give ozone a try. So I hooked this thing up Monday night and 3 days later tonight, my Achilles Tang is dead. No cuts or wounds, no signs of parasites or disease, was eating like a champ just this morning then tonight I found him dead stuck side ways on the overflow. I think he might've died a few minutes before I got home because everything on him was fine, not even missing an eye. Fresh, fat, clean, and dead. I really don't know what else it could've been but the new ozone generator I just added. All my other fishes are fine and I've got over a dozen other tangs doing great. I have my ozone generator plugged into my Apex controller with an ORP range of 300 - 350. Maybe my probe is off and the actual ORP is higher than that? But all my other tangs are doing fine. Maybe Achilles is more sensitive on Ozone?

 

[Ben.QLD2]

Almost certainly another cause, given other occupants are fine and you have a reliable ORP controller which is controlling the ozone. Has it been recently calibrated?

Cloudy water would typically be a bacterial bloom, or possibly macro algae, like Caleurpa so., going sexual. Both can drop oxygen levels, and obviously expose fish to large amounts of possibly harmful bacteria.

I have seen high ammonia cause cloudiness before, but it's got to be really high for that.

What are the water parameters?

What's the last change you made, besides ozone?

Did you slowly raise the ORP? What was your start ORP when you began ozone?

Any other livestock additions recently?

 

[mikethefishman]

The ORP probe came with my Apex that I got 4 months ago. Never calibrated it because it literally told me not to on the Apex app. It was reading about 250-280 before adding ozone.

Haven't added any new livestock since the water clarity issue 2 months ago. Was waiting to get that under control before adding anything new.

I've never tested for ammonia, phosphate, or nitrates. Back in my 125G or the current 550G. I just let the tank cycle for a month and moved my livestock over about 1/4 at a time. Going through QT and then into the new tank.

My pH is between 8.3-8.5, alk is 10.5, cal is 495, and mag 1450. This is about the same as my old tank and my Achilles tang has been in there for about a year.

Beside that new ozone generator, I changed the carbon media last week. No other changes in the last 2 months. Actually no new livestock in the new system at all. Everything in there is from my last system.

The ORP went up pretty fast actually, I was pretty excited at first. It was like 270 and it hit 350 in less than 12 hours. The water went from cloudy to crystal clear the next day. The Ozotech generator got this nob that goes from 1-10. I have it set at 6 and it feeds into my skimmer. Which is a Maxspect SK800 set at 30% power.

 

[Boreas_SA]

Do you filter the outflow of your skimmer through carbon? Achilles have very high oxygen demands, and ozone can possibly burn gills if it enters the tank by not getting filtered out through carbon, it is highly oxidizing.

 

[mikethefishman]

You mean the outflow from the skimmer to the sump? I have a bag of carbon siting on top of the skimmer to catch the ozone coming out of the skimmer top. Also I have a carbon reactor connected to my manifold from the return pump. The return pipe is 3/4" and it T's into a 1/2" manifold. So I guess some of the water will go into the display directly and some will go through the carbon reactor.

But no I don't have a carbon media bag from the skimmer output into the sump.

 

[mikethefishman]

I just turned down the ORP range on my Apex to 300 - 330, from 300 - 350. Just to be safe. Also I turned the nob on the Ozotech from a 6 to a 5.

 

[gbroadbridge]

I just turned down the ORP range on my Apex to 300 - 330, from 300 - 350. Just to be safe. Also I turned the nob on the Ozotech from a 6 to a 5.

Did the tank smell like ozone? If not, I doubt that ozone is the cause.

 

[mikethefishman]

There is a slight smell on the first day but I don't smell it anymore.

 

[Mike1970]

I’m running ozone with my achllies but I only run ozone at night for 1hr set the probe for 325 mine guy seems to be doing fine (knock on wood)

 

[iReefer12]

I only run my ozotech for 6 hours at night, not sure if you have yours always on? But even orp being low ozone can be high

 

[Superlightman]

I 'm pretty sure ozon killed my desjardini. I runned ozon since a while but decided to increase the time from a few hours too 24/24. Exactly same happened with him than with your fish. I