red clay typically has high iron levels --which can cause falsing issues depending upon how your machines set up discrimation wize -- wet conditions as a rule generally help with getting "deeper" depth --because wet ground is more conductive then dry ground which allows the same amount to electronic signal to go deeper into the ground --simple science 101 in action
dry hard red clay soil ( the red is from the rusted iron content in the soil ) is often times like digging in bricks - hard going