water change question

[sharelove]

Hi, I have my water change bucket with a heater in it and the salt mix. After sitting there for a couple of weeks now, there is slime and rusty type streaks down the sides. Should I use this water? I have a feeling that I've done something wrong...I used some other water that I had prepared after this one, and that water bucket only has a pump in it. The motor of the pump seems to keep the change water around the right temp. This water was fine. What gives?
thanks,
marc