If you're referring to the traditional method (electro-chem etch) I've never seen it successfully done in Ti. Electro-chem works on ferric alloys. Since there is no ferric (iron) in Ti, I don't think it matters what electrolyte used.
Most who "mark" in Ti, do so with a "laser engraver".
Ti can be etched but the result is pretty fragile so any mark would have to be protected from any wear. Use AC and only for a few seconds, it's almost instant. Hit it with a heat gun or torch to set it. Again, they really fragile marks. You would have much better results using ANNO and a brush with your stencil.