How do you know that it is in fact a chlorine stain unless you have been using chlorine tabs and the tabs are tossed, spilled or dropped into the pool. Tabs will burn the surface that it touches and often these stains are not removable.
Pebble sheen is the finish on the surface of a pool gunite is the cement that a pool is constructed from in other words you can finish a gunite pool with pebble sheen.