If you have a single DI, the SilicaBuster or better yet Super SilicaBuster would be my choice. If you have dual DI canisters than I would go with the MaxCap/Super MaxCap in the first position and SilicaBuster/SupersilicaBuster in the second. My current MaxCap and SilicaBuster cartridges are still plugging away at 0 TDS, believe it or not they were installed as replacements on 10/10/2011, I just checked my logbook, but will try the Super versions next replacement. I can't believe its been 16 months with zero replacements and still working.

The Matrikx +1 0.6 micron is a good carbon block. Don't know how prices compare, I think Spectrapure gets like $12 or $13 for their 0.5 version.