I read it's primarily produced with gaseous Cl and NH4, but who knows.
Just got off chat with BRS, and apparently the 5 micron carbon block is only marginally effective at removing chloramines and that the KEY to chloramine removal is no the polishing that the pentek chloramine block provides, but the catalytic carbon that one uses in place of the standard 5 micron carbon block.
http://www.bulkreefsupply.com/catalog/product/view/id/166/
ugh. in my quest for perfection, I'm ending up with way too many things that I'll never open, i just bought a set of new carbon blocks. Anyone need to BRS order?