Hello everybody - I live in Adelaide Australia and have successfully kept a tropical tank with common communal fish for over ten years - rarely do i have any problems - however,due to the 15yr drought our river water is getting a bit manky and the water corp are having to put lots more goodies in to make it drinkable - i did a small water change (3 buckets) 5 days ago and as a result i lost 3 large previously healthy fish of different varieties - need to do another water change - what can i do? do i double/triple the amount of water ager? can I use rain water? thanks and nice to meet you fellow fish loversxxxx