Here is what I recommend.

Buy a new sponge (not a treated, anti bacterial one, just new and plain)

Soak in distilled water.

Put in microwave until steaming and mostly dry.

get a clean plate, small enough to fit in the humi.

Soak and squeeze out sponge.

Put on plate in Humi.

Check sponge in a couple of hours, if it is drying out. Re-moisten.

Order the beads - just get the 65% IMO

Keep moistening the sponge and letting it do it's thing until the beads show up.

Activate beads and then start doing the same thing with them.

Use sponge to wash plate and put away.