Hi All, So I have a 30 gallon that I just set up in my home and loaded it with an imaginarium undergravel filter, a fake coral w/ air stone, an aqueon quiet flow40, a power head, topfin air-4000, a live plant (I think it's an amazon sword), rocky substrate, and this black bacterial substrate that's supposed to help with plant growth, and At the moment I've got one silver dollar. So what I'm trying to find help for is if I got the wrong substrate for an undergravel filter, and if I should take the fake coral back because it's been about a month and its covered in black (I think algae?) Gunk. Will upload pictures for reference as well. Any help or suggestions are both welcomed and appreciated.