I just received a Whites IDX Pro detector with "Bills" modifications. I have been detecting for 25+ years but could use any advice on the best way to set it up for use in the late 1800's to early 1900's yards and parks. Air testing it in my cellar, I noticed that I can get 2" to 3" more depth when the detector is in the "Black Sand" mode than when it is the "Normal" mode. Have any of you IDX Pro users experienced this? Please let me know. I need all the help I can get. Thank you. Dave