I have heard that the salt in Florida water isn't too bad, and a lot of single frequency metal detectors work fine. However, having said that, you always want to get as much depth as you can, while still maintaining an accurate level of discrimination. However, lots of beach/water hunters dig it all, so you can squeeze a little more depth out of it, as long as you can tolerate the constant chirping.
So, I would suggest you:
1) Try utilizing the true all metal mode. You will get more depth in this mode. You can also use your iron audio to rule out iron objects. The true all metal mode only gives a mono tone, with the exception of iron audio low grunts with that feature turned on. So, no high tones for silver, however, you still get a VDI number reading, so everything in the high 70's to 80's could be a possible silver target. Gold numbers often times show up in the 50's, however, can show up in the 80's also, depending on the "K" rating and what the gold is mixed with.
2) Try disc mode if you haven't too much luck or tolerance for the true all metal mode. For maximum depth/ stability, it's always the use of ground balancing and allowable sensitivity. Sensitivity is not a depth meter. Too much sensitivity can actually mask good targets, so you don't want to set it too high. For ground balancing, you have the option of the ground balancing window, which allows you to set a series of boundaries, where the detector will run stable. Or, you can just manually ground balance the unit as needed. May I suggest you hunt parallel to the water. Hunting 90 degrees towards the water puts you in a situation where the mineralization keeps changing as you get towards the water. Same goes for wet/dry sand. Hunt either, but not both without re-calibrating the ground balance and sensitivity.
3) A smaller coil will give you more stability in salt water or high mineralization areas. A DD search coil is also highly recommended in these areas. There are a lot of after market search coils available, and I haven't used any of them. Some people swear by them, other's weren't that happy with them.
Good luck! Hope you get some great finds from those Florida beaches!
