I have found both the standard mode and pro mode very deep. However, air tests support a deeper range on the Pro mode as shown below from some Garrett detector comparison charts a while back. If you are hunting in Pro Mode, it is wise to add some discrimination 20-30 to help eliminate some of the burps, beeps etc. You can always push the iron audio button to still hear all the audio if needed. You can add as much discrimination as you want, without losing any depth, unlike a lot of knobs on other detectors where you actually lose depth as you advance the discrimination knobs. Listen for those high signals, (VDI 75-85) which are found in the copper & silver range. Gold can show up anywhere, depending on its mass and what it is amalgamated with. However, gold and silver rings tend to sound out a lot louder, clearer and more stable in all directions using the searchcoil. If you are in a trashy areas, slow down, as the recovery speed is very fast, and too much speed with the coil may allow you to lose some of those great targets. And finally, the AT Pro, especially in Pro Mode, is very good at picking out good targets beside and sometimes underneath another piece of metal junk. Again, listen for those high tones, look at the VDI and dig all target bouncing between the 40's and 80's. Lots of surprises show up that way.
Good luck with your new AT Pro. Below is a graph comparing different modes using the AT pro.
Good luck with your new AT Pro. Below is a graph comparing different modes using the AT pro.