I have a question about a couple numbers on my fish hinder. I have a Humminbird PiranhaMAX 220. It is a duel beam. In the Upper right corner it displays my Upperrange and in the bottom right corner it displays my lowe range. What do those nummers mean? At the left in large numbers it shows teh temp and the depth, so I am not sure what those numbers are for and how I am suppose to use them.
Thanks for the help...