Tree Frogs: What should I use to sterilise the things in tank?

pebbles are easy. What you need to do is dilute Clorox real well and soak the pebbles in it overnight. Then rinse off the pebbles with a hose and rinse it out real good!! Then let the pebbles soak in a bucket of fresh water for a day or so and wham! your pebbles are ready!