rainsoft ec4 question

Hi

I have a rainsoft EC4 system, had it serviced last month, valves cleaned etc, the tech said it’s a great system that needs no maintenance and just valve cleaning etc once a year

problem is not my water smells terrible and is brownish in color.

I just want to ask your users opinion of what it could be, I don’t want to call the other guy back as he did not fill me with confidence, he took a chlorinator away with him from my old system, said I did not need it which I thought was a bit cheeky.

I know its hard to diagnose without seeing it, but the ec4 (3 tanks) says ALL SYSTEMS OK etc etc, any idea why water would smell and be brown?

thanks in advance