sump pit dry during wet summer

I've noticed that my basement dehumidifier has needed emptying more often than I can remember. I know we've had a really wet summer, but still. So I peeked into the sump pit today and its dry, to the bottom. I've lived here for over 13 years and in all that time it's never been dry. So, I'm in Michigan, and have a basement with the standard weeping tile on the outside of the house leading to a sump pit in the house. Several years ago, I put in a Zoeller M53 pump (float is Ty-wrapped in the on position to use as a SJE backup), SJE Verticalmaster switch, Zoeller-A-Pak overflow alarm, a Zoeller 503 water powered backup, and sealed the system with a 2" vent to the outside. I put a couple of plexi-windows in the sealed cover, but I haven't look at it much since then. Coupled with the humid air in the basement, do you think I might have some kind of blockage not letting water into the pit or am I worrying needlessly?

Did I put this thread in the right category?

Most humidity comes in through air leaks in the sill plate and/or passing through unsealed concrete.
Unless the water table is high, there will not normally be standing water in the foundation drains.