Sand Issues

So we have my mini sand containers but they are still confusing me like in class.  I just paw at a random one to see what gets me a treat.  Momma tried taking the screen off and letting me sniff the pink tube in the sand but it still doesn't help.

Momma had an idea to put some sand in the tube with the scent to see if that would work.

With scent and sand in the tube in mommas hand or hidden (interior style) I can find it no problem.

When put back in the sand bucket I can't seem to determine which bucket and paw at a random one in hopes of a treat.  hmrph!  Any scent work teams have ideas for help?!?!?!!?  I am stumped.

Pupdate: we found a blog that showed a similar problem with buried (but water) and the dog was having issues finding scent in the little bit of aquarium tubing.  So the pawrent put the tubing atop an upturned bowl.  Worked from there.  Made it easy to sniff.  Then put the aquarium tubing inside a bowl to make the flow mimic trial.  Last but not least added water just covering the tubing and eventurally completely submerging the tube.  It was a slow progression but the dog in the video really got it.  Here is our attempt with buried sand progression.

Sniffs,
Lucy