The "auto" GB probably won't work. You'll have to manually lower it to about 20 or a little less.
There is no guarantee that any GB adjustments will make it quiet, depends on the beach, and amount of mineral, hot rocks, and black sand.
Sure an all quartz (mostly white sand) beach not to much trouble. I've said this many times it is more about the mineral, and hot rocks than the salt. I know that just might start WW3, but is the reason that guy "A" says his machine works good at the beach, and guy "B" says his doesn't. I've experienced it myself within a distance of 100 yards, worked good where I started, and a 100 yards farther along it was terribly noisy, and NO amount af adjustments will make it go away.
That's just so you know if you can't get it to quiet down, it doesn't mean there is nothing wrong with "your" machine.
Good luck. Some beaches are the toughest places to detect, just like panning for gold, the waves have washed the lighter stuff away, and what is left is the heavies, iron rock, hot rocks, and black sand.