Hello and thank you for your inquiry.
The Chloramine filter will be placed in line after the sediment filter in an RO/DI system, but you must run two of them in series. Most "upgrade" kits will include a canister to give you this option. The new water flow would be: Sediment Cartridge, Chloramine cartridge, Chloramine cartridge, RO membrane and then DI cartridge.
You can view a video here on setting this up as well: http://youtu.be/BsJjbPfGPLE
If there is anything else we can do for you please let us know.
Marine Depot Customer Service