Okay, so I checked the water parameters two days ago:
pH: ~7.1-7.2
Ammonia: <.25
Nitrite: <.25
Temp: Varies between 77-78 F.
Yeah, so everything looked close to perfect, but that same morning I lost my betta. A couple hours ago there was an otto that was lying on the floor sideways, but was still breathing, so I left him there but now I can't find him. My cory now mainly resides in the far back right corner of the tank (same place my betta did before it died). I treated my water after my last post with some algae destroyer liquid and it worked alright. Water is clear again, but there is still this brown dust that resides on almost everything in the tank. I don't know if it is sediment from the flourite or the infamous brown algae. My plants still have minor melting issues, and my amazon sword has some leaves that are browning and fading. I have had my DIY C02 generator going at a steady pace and to counteract that I placed an airpump that pumps air slowly, almost as slow as my co2.
So my question is: why do my fish keep dying?