WaterMiser vent caps. Oh and check bi-weekly until you nail down consumption....
yes, considering water misers.
But these batteries are about a year old and have only needed light topping up once a month. What could have caused such a quick drop in water level? My old set never consumed much water all 8 years.
Perhaps long motoring on a sunny day? Combo of alternator and solar panels? But I have not changed the settings on either charge source since installing the new batteries and I know I have had long runs under power many many times since installing the new set of batteries.
The only thing new is that 2000w inverter. I've only been using it lightly on a regular basis until recently.
So far, after 2 days on a mooring, no sign of any water consumption.