New Problem, I have a RSM S400 been working flawlessly since June 2013. Lately I seem to be have a small issue with the level adjustment in the sump. It seem to fluctuate. The fresh water tank seems to be working fine (that was my first guess). Anyone has similar experience? Only idea/guess I can come up with is that the evaporation is higher than the fresh can replish it. I am using ~1.25 gallons per day. I have adjust the flow value a couple of times to compensate.