I used to add tap water when doing my weekly water changes until the city did a chemical flush one day after a main broke and the water was so bad, even my water conditioner couldn't eliminate all the bad chem. Now and for a few months I've been using RO water but after testing my tank water says it's really hard. I know my tap water has always been astronomically hard. Technically, the water should be all RO water by now, but I do add in Kordon NovAqua+ Plus Water Conditioner as my conditioner. It says it has bacteria and virus inhibitors, electrolytes, vitamins, and slime coat. Are these things what is keeping my water test readings hard? Does this mean I don't need an extra water conditioner for RO water?