So, I had a similar if not identical set up in my basement as the OP near Chicago. The basement was what is called a partial, so that about 5 feet was below the surface, with another 3 feet above, or just enough to place partial windows (window wells) for an emergency escape if there was a need.
The sewer lines to the street were above the bottom of the basement, so water basement drained down (from the washer, sink, external snow and water runoff outside), was first drained into a sump pit and then when it reached too high a level, the sump pump would pump the water up and into the sewer line.
If you are now hearing weird noises, it's something a plumber could look into. Normal noises are the pit being filled with water, the pump turning on, the water being pumped upwards, the pump turning off. "New" noises would in my experience make me worry about the pump or the discharge pipe having issues.
It's not something I'd want to wait too long on as if the pump goes out, I'm thinking that a basement flood would be in the works..
Yup I have pretty much the same basement. Except it's about 13 feet deep with full size windows for beyond easy escape. So how did your sump fair with the fish tanks? Were you going thru them constantly?