[justa-hairyape]

Have heard of sand filters being used to trap particulates. For example - The Scripps Institute Pier in La Jolla California has a filtration system where the public can get filtered seawater. But it is only sand filtered.

My PPM readings came from a handheld TDS meter (total dissolved solids). Think it measures conductivity. My RODI unit has a carbon prefilter and two particulate prefilters. If your filter can get 450-500 ppm down to 0 ppm, that has to be more then just sand.

[Terry Mross]

I don’t know what it is but it looks like very fine sand. Our water system is lousy. Our glasses look like there’s scum in the bottom and you can’t get it off with sandpaper. That’s from running them in the dishwasher and using stuff to stop it doesn’t work very well. The water is so bad we buy ice. Ice from the fridge stinks. The Zero filter does the trick. The drinking water from Zero tastes delicious.