De setting

[Aqua]

Do you leave your system pressurised all the time?

I did used to but just recently I had started switching controller off then opening pole tap for a couple of seconds to ease the pressure at night.

That might be the resin level that you can see there. I make my water separate from the van system so I don't have any air problems there. I can vaguely see my resin level in the DI though.

Im pretty sure its water level by the way it moved if I tipped bottle over slightly. Also I took top off and filled it up again and couldnt see it afterwards.