I'm up here in SF from Southern California for the holidays and many of us in SoCal have been dealing with a lot of water issues within the last few months. Most of us believe that they have increased Chloramine dosage into our water system which have been affecting many of our tanks. Consensus is to add an additional stage of water filtration to deal specifically with Chloramines.
http://reefcentral.com/forums/showthread.php?t=2613483
http://reefcentral.com/forums/showthread.php?t=2613483