This answer is not aimed specifically at you John, just generic readers.   Whenever you are looking for nuggets suspended in mid air it is very important to turn the ground balance off when running the TDI or TDI SL. The ground balance system is designed for in ground use and robs depth when working in very low mineral or no mineral situations. This is easily seen by testing a target with ground balance off and ground balance engaged. Raising the age old detector question - why use