Well, Ratz! The result of my bucket test this morning is about 100 gallons to evaporation and 200 gallons unaccounted for - so I still have a leak. The 200 gallons accounts for the 20-40 ppm of salt.... Fortunately, the leak is probably pressure side since I got similar results with and without the pumps on.

I have not compared my tester results to any pool store testing - have compared to test strips and have gotten ballpark similar results.