Does anyone know or messed with the navonics app you can use on ur phone. A question I was wondering not being from or local to grenada was that app has a water level adjustment to get what areas on grenada has water and wat is dry I was wondering if anyone has ever messed with it enough to know at say 200 ft what water level u set on ur navonics to get accurate readings ... It's not something I use for navigation just for refrence