Originally Posted by Andrew McFadden
Welcome to AA!
Do you keep it clean and also stir it up at every water change? Rocks and decor will sometimes turn black on the bottom and sides of it. Not sure why?? I'm thinking it's the gasses that get trapped when there isn't enough water flow touching it. It poses no threats to the fish or the water that I now of.
Ty I will make sure to lift up the ornaments to release any trapped gases when I clean.