How do you get in the bathtub on shrink ray island?

The Miniature Poptropica Blimp

This is the way off the island for those using the Sneak Preview, or if you have to leave and come back while you are tiny. Use it like the regular blimp.

The Balloons in the Living Room

You use the green balloon to help you get the key to CJ's Diary (it is in the Tresure chest in the aquarium in the Living Room).

Get the screwdriver from the kitchen drawer and take the battery out of the toy truck. Put it in the remote control and turn on the TV. Climb up onto the antenna (aerials) and you will pick up a static charge. Jump to the TV again and then left onto the green balloon, and you will stick to it as it drifts left to the highest picture frame. Jump to the shelf below it, and spill some fish food off the shelf into the aquarium (this distracts the fish). Then turn off the filter (aerator) on the right side of the aquarium, and you can dive down to the treasure chest where the key is.