The bottom well of my sump pump is black and Slimy Scum… how do I get rid of.
The hose from the air conditioner, drains into my Sump pump . It was a clear hose … now it is black . I believe the black fungus is growing up the pipe. . The black slime feels greasy … Like oil … but does not float on the water. . My main pump and my backup pump are both Black because of it . (they were a celery Green) What can I do ? My prior house always had a clean looking sump pump. I had cleaned it with bleach water. Doesn't go Away!

Not uncommon in either the sump or drain pipe. Water sits there and algae will grow, wastes will accumulate because the sump never completely empties. You can heat up a big pot of boiling water, put some dishwasher powder in the sump, pour the water in and scrub the sump with a long handle brush and agitate the water. Let it sit for a couple of hours and pour water in to activate the pump. Usually will help. The drain line is easier to replace. Get a piece at HD and a barbed connector, push together and put on 2 hose clamps.

Thanks! I'll give the hot water and Dish soap a try... The hose runs up through 20-25 feet of dropped ceiling. To the Furnace. And through some finished walls.

Good call Ma064,
I was going to suggest boiling water plus bleach to cut the slime.
Liz, let us know if that worked. Good luck, Tom