Gotta agree with Geoff: a TDS meter is unlikely to tell you much about
chlorine. Pool test kits use either orthotolidine (called OTO in the
trade) or diethyl-p-phenylene diamine (DPD). I think DPD test kits are
more sensitive than OTO ones, but I'm unclear if pool test kits are
sensitive enough to pick up whatever level of chlorine that is in town
water and that is likely to damage an RO membrane.

AC filters definitely reduce chlorine in town water.

One secret to using an AC filter is to reduce the water pressure (ie
have a low flow rate through the AC filter). The idea being that the
longer the town water is in contact with the activated charcoal (AC),
the more likely the chlorine is to be adsorbed onto the surface of the
AC.

Bil