About two weeks ago I noticed that 6 juvie Discus in one of my grow out tanks looked bad. My first reaction when fish look sick is a water change, so I went ahead and did a 50% change using straight R/O. 4 hrs later they were all dead. I don't like losing fish so I decided to play detective.
All tested water parameters were as close to perfect as you can get. An autopsy on the fish revealed bleeding, not just inflamed, gills on all the fish. The only thing I could think of was chlorine. I contacted my water co and asked if they had changed anything recently. They said because of our recent heavy rains they had increased both chloramine and chlorine levels substantially.
So everything points to chlorine poisoning, but I used R/O water so how did the chlorine get n the tank? I have a friend who works in an environmental testing lab - she offered to test my R/O water. Bingo!!! The increased levels of chloramine/chlorine had overwhelmed the carbon filter in the R/O unit and then destroyed the TFM. So what I thought was nice clean R/O was actually just filtered water.
I have a separate R/O DI unit in my garage that I use for all my Apsto tanks so I didn't lose any. Also now I keep these little chlorine test kits handy, courtesy of my friend the chemist, for when the rains come again (if they do - I live in Central Texas and rain can be a novelty here).
I guess the moral of the story is never stop checking, cause when you do the fish gods a gonna bite your butt!
All tested water parameters were as close to perfect as you can get. An autopsy on the fish revealed bleeding, not just inflamed, gills on all the fish. The only thing I could think of was chlorine. I contacted my water co and asked if they had changed anything recently. They said because of our recent heavy rains they had increased both chloramine and chlorine levels substantially.
So everything points to chlorine poisoning, but I used R/O water so how did the chlorine get n the tank? I have a friend who works in an environmental testing lab - she offered to test my R/O water. Bingo!!! The increased levels of chloramine/chlorine had overwhelmed the carbon filter in the R/O unit and then destroyed the TFM. So what I thought was nice clean R/O was actually just filtered water.
I have a separate R/O DI unit in my garage that I use for all my Apsto tanks so I didn't lose any. Also now I keep these little chlorine test kits handy, courtesy of my friend the chemist, for when the rains come again (if they do - I live in Central Texas and rain can be a novelty here).
I guess the moral of the story is never stop checking, cause when you do the fish gods a gonna bite your butt!
