Ok, think I will shed some info I got from a guy whos been doing this hobby for 15 years. He lives in the country and uses well water for his fills and top off. One day about 4 months ago, he was noticing his nitrates were very high and decided to do a water change. He did 60% at one time and wham all fish and inverts except for Corals died. I know this sounds like a recap of Haras story, however, this is the truth. He had very expensive fish in there and I got into a heated conversation because I asked him why 60% at one time. Come to find out, there were contaminates in his well water and it passed all of the tests he had until the city tested it because he noticed it didn't taste right. It had some sort of bacteria in it that was caused by what they said, and get this, rainfall and the nearby creek..I thought it was a load of crud myself, but, He has since gotten an RO
unit and things are fine...He now uses it for drinking water too. All of his new fish are well.
PS,,,he explained to me that the reason for such large water changes was that he did not believe in skimming and DSB
's go figure. To each his own right?