Does anyone know why the percentages on my Aquapure 1400 would change to 0%? It was set at 80% pool and 10% spa and everything was working great. The family and I left on vacation for a 5 days and when I came back I tested the water and showed 0 chlorine. When I checked the chlorine output both the pool and spa were at 0%. Any idea why this would happen? Thanks in advance. I am still new to the salt water scene and am trying to figure everything out as I go along.