Reading your postings over the period of time R2k2, I notice that you are constantly changing the quality of your water. Is your lfs using the same water authority as yourself? If they are and you are trying to change your water quality to match that of the wild versions of your inhabitants you will be causing yourself problems. the fish you have will have acclimatised to their surroundings/environment and if you are trying hard to give them the match that they would have in the wild well you are putting them under more stress than they need to be. As Davy,pete and ken all say, once you start a change you must keep that quality up forever. If you are new to this then I would advise that you have a few more months under your belt before experimenting. Please don't take this the wrong way,I'm all for NATURAL ENVIRONMENT, but when your fishes are probably bred in this country anyway with probably the same water quality as your own why change it?