If you take out a gallon of tap water and leave it somewhere to evaporate fully, or heat it to force evaporation, is there any residue left in the container? If so this is what gets left in your tank for every gallon that evaporates. It will likely do-in your tank chemistry.
yeah, if your water is anything like the water in my area, phosphates, nitrates, etc are really high and are going to cause trouble... especially algae. bah!!
yes of course an ro unit is what you want to work for seabass but for now try to at least let your water set for more than an hour. you really do need it to sit a day or so with a PH running in it... sounds like things are getting betting all the time tho...