Step 1: Materials
plastic tubing - I used 1/4 inch, but its not critical, it just has to fit the aquarium pump.
two nesting containers - I used yogurt tubs
two cable ties
Step 2: Sponge Preparation
Then stab a hole for your tubing
Step 3: Container Preparation
Next cut a hole small enough for your tubing to fit through.
Step 4: Bubbler Assembly
Then shove the sponge into the larger hole.
Step 5: Final Assembly
Once you are happy with the results, you can poke some holes near the top and zip tie everything together. Make sure to secure the tubing with one of the ties.
We used it outside and in the kitchen with dish soap, and in the bathtub with bubble bath.