jimmie,
You can't expect to buy a detector,jump in the water, and find something (even if you Know where it is although that'll make it easier). Try turning up the Disc. to about 5 or 6 & the sensitivity back to 8 or so.search the area where you lost the ring (if you can test the setting on a similar ring that should help). Try to be methodical in your searching by marking where you start and stay in an area. If the ring was just lost it should be close to the surface (if the area doesn't get stomped) and give you a good repeatable signal. swing as slow as you can and try to keep you search sessions short or your going to get a headache,frustrated and want to wrap the poor detector around the closest fixed object. If you don't find it at that setting start to turn down the disc. gradually. There are many variables that can affect your search if the ring happened to land on or in close proximity to a nail or other large piece of metal your going to have a tougher time finding it,if the ring is broken at the solder joint you may not get a signal until you are running at zero disc. but unless a bass ate it on the way down it IS down there. I only have a 1280X & I dig every signal (millions of pennies & nails) but I have found some cool stuff also. It will find your ring I found my buddies wives diamond stud earring under a swing set at a park so anything is possible. If you need more help let me know I'll do what I can.
Good Luck,
Troy