Help! - Best detector for gold ring lost on salty wet sandbar

Still no luck - I've been out several times with the Whites Surf PI dual field. I did find someone else's wedding band & reported it to the nearby hotel, but not the diamond ring I'm looking for. I've found a lot of coins & fish hooks too. Dug so much stuff that I've already cracked my scoop that I bought from Kellyco. Oh well, I guess I'll keep trying. Thanks again for all of the help/suggestions.