False signals are signals the detector provides that indicates it has detected metal when there is actually no metal present in the ground. This occurs in mineralized soil when particles like iron oxides and salt cause a response in the detector. The usual way to remedy this is to ground balance to cancel out these ground signals. What it does is the metal detector matches its ground balance to the phase reading of the ground. In highly-concentrated soils, it may reduce some but not all noise, and this is usually acceptable to the user. If not, your only option may be to reduce sensitivity.