I have something similar looking that I'm planning on putting shrimp in, only its around 3 and a half gallons Problem is, I can't seem to find any locally lol. Can't wait to see your progress though!
I have absolutely no idea what this could be, but i'm very interested as to what you find out. And if it was something chemical wouldn't it show up on the test kit somewhere?
True, true. Maybe if I can mess around with the paint in the cracks I can make the depth seem more profound. And using the chisel to rough it up sounds like a great idea too! Thanks.
Usually Tetra Whispers and most HOB filters that I have seen have the two parts shown below: The white media bag is mainly used for filtration and can contain bacteria and the black mesh piece holds bacteria as well. If you have that or something similar that both provides filtration as well as...