The discoloration can be caused by other factors. Without actually coming to you house or getting a sample of your water as I personally do for all of my customers, it is very difficult to determine what is causing the discoloration (or odor if you have any).
Have you tested for tannins? The equipment you have will do nothing for that problem. Is your plumbing very old? Galvnized?
We occasionally set up systems similar to yours with a few changes. We use an accelerator between the chem-pump and the retention tank. This helps mix the solution for better blending. Also, a test valve/port after the retention tank to test sample the water before it goes into the carbon filter.
I can't remember if you state how much sulfur in ppm your water has. Do you have that info?
We normally use H2O2 instead of bleach. Not sure if backwashing EVERY day is recommended but it may be necessary. If you are getting odor when you use 'lots of water' then your settings are up to it.
A dual or twin tank softener is what I would recommend.
You still have some hurdles to jump but more info would help.
Andy Christensen, CWS-II