very pretty. and your vet sounds awesome!
about the pebbles, keep in mind that turtles grow pretty fast in the first year so his head will soon enough be bigger than them!

plus all the dirt and grossness hides in the pebbles and the water quality is compromised. your filter isn't very powerful so it won't be able to really clean the water very well.
when you upgrade to a bigger tank, i'd get rid of the pebbles an find some large river rocks and driftwood to decorate with.