I have 2 different clip on's, a planet waves, and some other one, and they display as D#. Every note should display when you are close to it.

(I had to post again just to tough out my Eb statement. I should just stop posting.)

But, yeah, D# is how every tuner (2 clips, 2 pedals) I have will display the next note down from E. I'd bet money on the Snark doing the same.