NewMarket Naturals makes modular shower filters which can accomodate some of the more efficient showerheads out there. They also make a April Shower filter which is compatible with the Oxygenics showerhead we recently featured. Available from: NewMarket Naturals.
This bath filter removes 90% or more of free chlorine, improves lathering with quartz crystals. You swirl in the bath water for a few minutes, for filtration to occur. Available from: Natural Baby or Ebay