I have dreamed of purchasing some discus. I know I would need to reduce my water hardness from tap water. However I just tested my rainwater and it said it was very soft. Do you think I could catch rainwater to use or is this dangerous? Do you think their is a way to filter my rainwater of harmful contaminants if any or do I just need to use distilled or reverse osmosis filters? I had asked my fish store man about keeping discus. He said if I had just wanted them as fish they should do O.K., but if I wanted to breed them then that is where the picky water conditions come in to play. What are your thoughts?