I've been chasing this problem for a few months now. My well pump loses prime and throws air into the lines if I run the system hard - that means doing a large load of laundry, dishes, flushing toilets etc all on a busy morning. The largest culprit of this is a toilet that likes to seal improperly and run. If I miss that and don't wiggle the handle, I lose water.
The system holds pressure overnight - there are no leaks in the system.
Waiting a bit, re-priming the pump and then running it again gives me back (airy for a while) water. This seems to point to the well running dry. What confuses me is that this happens regardless of the water table level. I live on a sand peninsula with serious flooding issues - while the water table was well into most people's basements, I was still losing water quite often.
The previous owners of the house seem to have done some sort of calcium treatment to the well (I found an old bottle of calcium treatment tablets in the garage), but I'm not sure a) how to use them and b) how that would prevent the situation I'm having now (my water does not seem overly hard).
What are the next steps I can take to diagnose this problem?