Hello everyone! I have been running a series of tests to get the best out of my classic IDX. I ran a complete air test on a Morgan dollar, Peace dollar,Franklin half, silver quarter, mercury dime, buffalo nickel and wheat cent. I found that the best depth came from setting detector at highest sensitivity, black sand mode, no discrimination.the greatest depth was the peace dollar at 10-1/4 inches, with the shallowest depth being the Mercury dime at 9 inches even. I thought I would've gotten greater depths with the air tests. Thoughts?