CO2 and Oxygen levels are independent of each other, and although CO2 can get high enough to nuke things that doesn't sound like what happened.
I had Süßwassertang in one of my aquariums a while back. Mine got to be a decent sized mound. Keep an eye on it, I imagine over time it might break
what symptoms do they show?
What are you using to monitor your C02 levels?
what is your water temperature?
Ok, I'll start off by saying that I have raised fish off and on for 20 years primarily Discus but I am really stumped with this one. Right now I have
All A. barteri nana sold.