The cheapest 13X zeolite I could find was: http://www.overnitesupply.com/13x.aspx I used the smaller bead size, somewhat based on this paper: http://engineering.ucsb.edu/~yuen/references/ref-2.pdf I did try grinding up the 13X to get an even larger surface area, but results were inconclusive. The Sweet PDZ (below) is somewhat powdery even in it's granular form.
The natural zeolite is clinoptilolite called Sweet PDZ and bought from Tractor Supply: http://www.tractorsupply.com/en/store/sweet-pdzre
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