Ok, yesterday I did a fast test and came to a conclusion.
I have buried a small 19,2kt ring ( 7 ID) at around 25cm, wet. On Beach 2, Max sens, 50 tones, FE&F2 at 0, Recovery speed at 5. My Ferrous tone is set from -9 to 0. I had no issues picking up the ring.
I switched then to Field 2 with same settings, but with standard tone break ( Ferrous tone set from -9 to 1). I had no signal from the ring and there was alot of falsing coming in 2 ID!
I guess everything was just fine and completely normal, I mean, the higher frequencies will pick up to much salt mineralization and