I have a SWG in my pool system. I opened the pool in late May. Tested the salt level. Was 2200. Added 160 lbs of salt, and the red light cleared on my generator and everything worked fine. Tested again at the point and it was 3400. Ok everything is great. So today I tested it with my monthly testing and it was 4000? I did the test two times and got same number both times. Is this possible? Can the pool gain salt?