If you are using the Explorer on the dry sand, you should do pretty good. If you have a water detector and are on wet sand or in the water, surf and wind conditions will dictate how well you do. Of course location will also. South Beach is rated the best and probably is because of all the traffic. However, I had my best luck and enjoyed it more at less congested Jupiter beach.
What I did was to stop by Reilly Treasure Gold in Pompano and talked with the dealer there and the guys that seem to hang out there. They gave me a good tip on where to hunt, and also allayed my dispair at not finding much. The reason was because the weather and wind conditions had the beach sanded in and none of them were finding much either. I did manage to come away with one nice gold item before I left.
There is a book or two that you can buy from Kellyco and probably a few other venders before you go that gives all of the information, restrictions, etc. You can also get them at Reillys. I studied those books before I went and had a pretty good idea where I could hunt before I arrived, and had a real good GPS in my vehicle to make sure I could drive there without knowing the area. I had a great time, and next time I'm hoping the conditions are better because my water detecting skills have improved.
Of course, I was mostly using an Excal 1000. I used my SE and F75 on the dry sand, but had the best luck with the Excal. Using pretty much any detector, you are going to find a ton of beer bottle caps there if you are going to hunt in the gold range. You just have to deal with them at first to make sure you are not missing the gold. After awhile, you can usually tell them apart.
Another tip you might consider if you are going in the surf is a wet suit and diving boots. This will protect getting stung by jelly fish, man-o-war, etc. and the boots will also keep the gravel from under your feet. I didn't get stung, but I was worried about it. I had wore Crocs on my feet, but had quite a bit of trouble with the surf washing gravel in them. So that might be something to consider.
I hope this helps!
HH Alton