New owner of a Bailey Adamo, and also started to find the fresh water tank level a mystery. I drained the tank completely then manually added 5l at a time then checked the level readout. After adding 30 litres the readout was 16%, after 60 litres 34%, at 70 litres 44%, it then raced up and when I had added 80 litres I had a reading of 97%. The strange lower readings are probably due the the irregular shape of the tank. The other mystery is at 80 litres the tank was completely full, very strange for a 100 litre tank.