Anyone familiar with this sort of problem? It's a black, hairy mold. I've replace it once due to leaking, and it also had the same problem. This one is 'sweaty', but there is no leak. Any help would be appreciated. Thanks for your help.

luckylugan

If your toilet is seeping from a defective fill valve or tank bulb or flapper this will cause condensation on the out side of the pipping and mold will end up on the piping thus you need to find the source of the leak and then use bleach to kill the mold... follow directions on the container

Sounds like that very well could be it. Thanks for your help.

Your more then welcome