So I found a 29 gallon tank on the side of the road with the stand. Just filled it with water to see if everything is okay. Looks like so far it is holding the water. As I was filling it with water I added vinegar and started cleaning it a little bit. When I was cleaning one of the corners I saw what looks like to be some black mold under the silicone. Is this something I need to be worried about? Do I need to Reseal the tank? Is there anything I can do?