Aloha, I am looking for advice on which metal detector to purchase for searching out old privies and trash pits. I live in Hawaii where the ground is heavily mineralized due to volcanic rock. I am looking into a pulse induction type md, however, I would like to talk to others who have used metal detectors for this purpose. I need to detect cans, pots, and metal tools 4 to 7 feet deep. I look forward to hearing from you. Thank you in advance for your response.