Buckeye Hydro
Guest
Why pack DI resin tightly? Good question.
Realize that in the RODI systems common in this hobby water flows UPWARD through the mixed bed DI resin. Mixed bed resin contains both anion beads and cation beads - so it deals with positively and negatively charged ions.
If the resin is not packed tightly, the bed will fluidize, and the anion and cation beads will separate. The heavier cation beads will settle to the bottom, and the lighter anion beads will rise to the top. It will appear like the top portion of the resin bed has changed color because typically its only the cation beads that have the color changing indicator. When this happens you essentially now have separate beds, rather than a mixed bed, and your output TDS will climb a bit.
Russ
Realize that in the RODI systems common in this hobby water flows UPWARD through the mixed bed DI resin. Mixed bed resin contains both anion beads and cation beads - so it deals with positively and negatively charged ions.
If the resin is not packed tightly, the bed will fluidize, and the anion and cation beads will separate. The heavier cation beads will settle to the bottom, and the lighter anion beads will rise to the top. It will appear like the top portion of the resin bed has changed color because typically its only the cation beads that have the color changing indicator. When this happens you essentially now have separate beds, rather than a mixed bed, and your output TDS will climb a bit.
Russ
