If adding chlorine caused green water to deposit rusty brown stuff on the pool bottom, you've got iron in the pool.

Short answer (you'll need a long one later):
#1 - Get a chlorine compatible liquid metal control agent for pools and FOLLOW label instructions on dosing -- do NOT over dose!! Best to get this from a pool store because the Aqua-Chem stuff that now seems to be at all Walmarts and Kmarts is junk.
#2 - Get some polyquat 60 (see www.poolsolutions.com/gd/polyquat.html ) and add a treatment dose -- follow later with maintenance doses.
#3 - Run your filter 24/7
#4 - Tell us what sort of pool you have (gallons / pump / filter) and whatever test results you have.

The metal product will help keep remaining metal dissolved; the polyquat will help keep your pool from getting algae while we work this out.

Ben