Hi Brilliant,
You can either use your detector in "Fixed Balance" or "Ground Tracking". If you haven't selected the Ground Tracking button, the detector will automatically be in a "fixed" Ground Balance. If you walk from one type of soil to another, the Ground balance will likely change. If this happens, you should rebalance your detector. If you don't, you may end up with ground noise and interference that make it hard to hear targets. Press your Tracking Button (in either Coin/Relic or prospecting Mode) and a little symbol will appear on the LCD in the upper right-hand area. It looks like a squiggly snake with a line through it.
When you press the Ground Tracking button (located on the right side of your control box interface), the X-Terra detector will then quickly scan the soil very fast for a few seconds and then it will constantly "sample" the ground as you walk around every so often. As it does this, it is adjusting the Ground Balance of the detector and allowing for variations in the mineral density and even soil type. For example, you might be walking over dry sand with moist areas and perhaps even different types of ground composed of iron ore, sandstone or quartz sand etc. With Tracking on, you should be able to avoid needing to rebalance your detector too often.
However, if you find a target, you should immediately turn Tracking off. Because if you leave it on and continue to sweep the coil over the target, the detector may assume you are simply walking over a pocket of mineralized soil and may likely ignore the target signal by "balancing out" the target.
Cheers,
Marco