The 505 only manually ground balances in All Metal mode as far as I've understood. If the machine auto ground balances in any other setting then so be it. I've had a 505 for a few months and with the stock 8.5" coil and my soil conditions I see my depth limits at about 5 to 6" max on coin size targets. Because of the semi trashy area I hunt I usually set it in discrimination mode with the sensitivity about 2:00 and discrimination at about 12:00. This eliminates some of the lower trash but also gold so you need to be aware of this. It's probably best to start with the discrimination at around10:00 and dig everything until you get a handle on what the 505 is telling you about your targets. Do your own test on various coins and trash items in your soil till you can come up with some settings for your area. You can also test a gold target the same way to see how it sounds off and registers to understand how you may miss it if discrimination is set to high. Best thing to do is in discrimination mode is set sen. as high as the 505 will allow without false beeping and discrimination completely off and dig everything till you get through the learning curve. Good Luck
