I recently purchased the Omega 8000. I haven't really used it yet because it's been to cold or raining. However, I took it outside today and practiced using the ground balance. After ground balancing (auto) to zero bars I tried to detect coins that I buried today at 4'', 6'', and 8'. My detector would not give a signal on neither.Air testing everything is find I know that the coins don't have the halo effect yet but should this be a concern. . I have detecting experience but not with the Omega. Thanks.