The F75 is a multi-purpose high-performance computerized metal detector. It has the high sensitivity and ground balancing control needed for professional gold For any one new to the F75 ,it may help if i just give you a few tips on using "Manual Ground Balance can only be performed while in an All Metal mode,The thing is: In the manual it says: Select the MANUAL G.B. and then The message "PUMP COIL TO G.B." will appear. On my F75 that message (" 1. Find a spot of ground where there is no metal present. 2. Hold the detector with the searchcoil about one foot above the ground. 3. Push the TRIGGER SWITCH Page 16: Fisher Labs F75 Users Manual. Ground Balancing (continued) Search Techniques (continued). The F75's other processes have a reputation for