Hello Emmy,

You need to lower the string height (known as action) at the nut and bridge and bring the strings closer to the fingerboard. If you try to fret notes with high action, the string bends and plays out of tune. / The string height for regular playing (fretting notes, chords, etc) is about the same for bottleneck slide. "Possibly a little higher, but you still want to fret notes over the entire fingerboard easily". The "correct string tension" for the slide to ride on the strings correctly so you don't bottom out and hit the frets is a balance between string gauge and tuning. Use at least medium gauge strings. Lower tunings below standard tuning (EADGBE) like Open D (DADf#ad) use heavier strings. On CBG - GDg or DAD. Higher than standard like Open A (EAEac#e) use lighter strings to take the pressure off the neck. On CBG - this would be AEa or EBE. I hope this helps. Enjoy, Keni Lee