MIEX is a strong base type I resin whereas they impregnate iron into the copolymer during solution polymerization. Their niche is removing color form water using low volumes of salt ( 3-4 #/cf salt)to regenerate thee resin.
im not sure why one would use MIEX as a prefilled prior to RO since a UF performance would be a better option.
yes I do have a lot of information with MIEX since I competed against them in Florida. Basically MIEX are really small beads, 200-400 micron OD I believe.
How can I forward you some info? FYI, let me know what you are investigating, there are a lot of other options out there!