Efflorescence Removal from Patio Stones

Hi - I installed a large patio last summer, and it survived the NE winter. When I put the stones down, a lot of them had efflorescence on them. The stone guy where I bought them told me it would go away, but if not, get an efflorescence cleaner next spring (which is now). I went to the hardware store and bought a product (I won't mention the name because I'm not sure I can in this forum), but the word "Etch" was part of the label name. Got me a bit worried ($3000 in materials, didn't want to mess it up), so I called the stone manufacturer, who told me the product was good. I have followed the simple directions, but the stuff isn't budging really at all. Can anyone recommend a product of technique as to how to get this stuff off? We are thinking about applying a matte-/gloss-finish sealer, but certainly can't until this stuff is removed. I'll post pics if necessary. Thanks - Dave