Idea department! Most water tanks have three level readings that really don't mean much. Empty fresh water tank and fill using the meter. During fill - mark sides of tank with a sharpie in say five gallon increments. I am getting one also.
Suzie & Chuck USNR USAF USCGA Challenger Owners Club 2015 37KT Challenger, Demco Commander tow bar, Ready Brake, Sewer Solutions, Safe-T-Plus 41-230, 5-Star tune, towing 2017 Ford Edge FWD 3.6L V-6 four down & 385 FastTrack kayak in the basement.
Summer - Creede, CO Winter - Okeechobee, FL