Depending on your system, VER's response would work.
As for chlorine, your contractor may be using low pressure polyamide membranes which cannot see chlorine. Therefore, it is generally best practice to have the RO unit continually running to limit biological growth in addition to limiting...
You should contact the people at Crane Environmental if you're on the east coast or Membrane Systems Corporation on the West Coast.
They both specialize in small RO systems and can either provide you services directly or direct you to vendors that can supply cheap and appropriate systems for...