A properly running rodi unit will remove the chloroamine. Some hobbyists in areas where a lot of chloroamine is run for water purification, use
two in-line carbon filters and make sure to replace the DI filter before it becomes saturated or you can dump a lot of ammonia in your system. Change the DI filter as soon as your TDS meter rises from 0 to ..1 to prevent an ammonia dump into the rodi water effluent.
See this article written by Randy:
Chloramine and the Reef Aquarium
http://www.reefkeeping.com/issues/2003-11/rhf/feature/index.php
From this article:
"Lessons Learned and Suggestions:
1. Most RO/DI systems seem capable of removing chloramine adequately for aquarists.
2. The carbon cartridge may become less useful over time, and it is possible that the chloramine removal effectiveness of a system may be lost before the DI appears to need changing.
3. Cheap sediment cartridges may expose the carbon cartridge to unnecessary fouling, which may permit chloramine to pass through the system. Cartridges should be replaced as soon as the pressure drops significantly, even if RO/DI water is still being produced at a reasonable rate or purity as measured by total dissolved solids.
4. Testing for chlorine and chloramine is easy, so any concern is easily reconciled.
5. One Hach kit provides several dozen test results. Our local Boston Club bought some kits and had a "water testing day." The kits can also become part of the "library" of a local club for aquarists to use once in a while to see if their systems are functioning. That way, the cost to each aquarist is minimal.
Conclusions
Chloramine in tap water should be a significant concern to aquarists. Its peculiar properties make it well suited to disinfection of water supplies, but also make it a potential toxin in aquaria. In order to render the water safe for use, aquarists need to use one of two systems for purification: an inorganic reducing agent combined with an additive that binds ammonia (or a single product that does both), or an RO/DI system. Chloramine is toxic enough that it would seem prudent for aquarists to spend the time and money necessary to ensure that they do not unduly stress their organisms. This activity includes setting up appropriate purification systems, and may also include testing the water to ensure that those systems are functioning properly."