Ahoy,
Some further info.
I fully agree. Use water for storage and TE for working solution. As bead synthesis requires harsh conditions it is advisable to re-suspend them in a buffering medium to guarantee that any remnant hydroxide anions (silica beads) or hydrogen cations (carbox. beads) are neutralized and wont interfere during consequent steps.
However I would not recommend TE as the permanent (many months) storage solution as Tris will chelate metal ions and thus potentially mask deterioration of Beads which in water would show as slow browning of the supernatant. Depending on the shell thickness and quality of beads this might be a matter of many months if not years.
Tim M