Hi again Thanks for your feedback. I've filled the tanks a number of times now, using both a hose from mains pressure and using a 12v pump and filling from a jerry can. On all occasions I've filled slowly and let both tanks overflow, so I know they are full. I used the water until it was spluttering out of the tap in the sink, due to too much air coming out. When I refilled the tanks, I was only able to get 120 litres into them, before they overflowed. When I looked at the positioning of the outlets, I can see that they are approximately 25mm from the bottom of the tanks, so it seems to me that I'm not able to access all of the water in the tanks. As we spend a lot of time in National Parks and other sites where we can't connect to mains water, we need to be able to use all the water we are carrying. I'm waiting to hear back from Ashley at Kedron to see if he can help, so I'll let you know how I go. Has anyone else done the exercise above of seeing how much water they are actually able to get out of their tanks? If so, please let me know. Cheers Meg & Marty