have a unit i picked up from a member here for 25$. never used it. don't know how good it works but i do know it needs filters. u can have it free if u come pick it up from flatbush brooklyn
will kick u some pics tonight when i get home from work. take a look and if u want it, i can even meet up with u in manhattan or so. it's just gathering dust right now.
Excellent question. That brown stuff is the DI resin. Part of what makes this particular brand of RODI inferior to other brands is that DI cartridge. A better quality DI cartridge is hung vertically as opposed to laying down horizontal. I think you can even see in that photo that the water forms a 'channel' above the resin and doesn't even flow through the DI resin. That is why a vertically hung DI cartridge is more efficient.