Rich Acugage
Rich:It calls for 1/2" from top and bottom, but where you put the tape on the bottom is where it will read empty. So you are fine at 7/8".Installation is very simple. You clean the tank off where you are going to put the tape and we supply a special adhesive to prevent the tape,(which have adhesive on it) from peeling. You attach two copper pads which have a module tied to it. The copper pads can go anywhere on the foil. Next you have three wires, power, ground and signal.The calibration is simple also, after the installation you fill the tanks and you calabrate to full. It does the rest. You only have to do this once.This is about it. If you have anymore question please mail me at.Dennis@snake-river.orgThanks so much for your interest.Dennis