I got the tank from Gardiners, think I'll give em an email, and ask them.
I am sure that what you see in the tank (looking from the outside) is what you have.
The baffles are in place to restrict water movement within the tank but do not influence how the water actually levels out at. The exception would be if the vehicle was at an angle forcing the water to one side rather than actually level.
Hm, that's what I'm not sure of, they displace water, simple illustration, if I'd have a glass of water, and I would dump something in there, the water level changes, same thing I reckon happens in the tank, so it would change the level?
Install a water meter that will give you the answer.
Watermeter, yes, but the problem is......I don't really want to put 400litre of unpure water in there, otherwise it first has to go through the RO, and then you have to take off the waste etc. That's a bit difficult. Or are you talking about a third party watermeter, that you place between hoses? How much would that be?