I agree with Walrus. When doing sand/beaches, I always run in All Metal Mode on the AT MAX. For whatever reason, running otherwise, you'll miss things. They just don't hit hard on the Max in the sand. I spent about 4 hours in Custom, and my son was using his AT Pro. When we returned from the same section of beach, he had about $4.50 in quarters, and I had NONE. Only a dime and a bunch of pennies and nickels. Something was wrong. The next night, I turned it to All Metal, and ran the right side of where we started. I netted about $5.00 in quarters to his $2.50. We confirmed this by burying quarters, and sure enough, with a normal swing the Custom mode just wouldn't grab them everytime. All Metal sang out like a bird.
It's easy enough to look at the display and rule out if you want to ignore an iron signal, but if it's got any "weird" to it, at all, dig it, as fine gold chains, and small earrings can ring up low.
Cheers!