I installed a fill plate for a fresh water tank and am looking for a way to tell how full it is from inside and when to stop filling from outside. The fill plate is next to a cabin window which has a bulkhead that some kind of indicator can be mounted to. I have some contactless level sensors and can program them to work with an Arduino if using an LED, LCD or other screen. What types of indicators have you found that are visible in sunlight or semi-shaded spots and do not require a lot of power? I'm not opposed to an analog style meter