No I wasn't - I had incorrectly assumed the liquid level in the column was the same as in the tank. Thought the triangle symbol was maybe a smudge of a scan. The head is 6.7m?No. That is not the pressure at the bottom of the tank.
I told you to forget about the tank, and to focus on the column of liquid on the left. The ideal gas law will not be part of the solution to this problem. Looking at the column of liquid on the left in your figure, did you notice that little triangular "symbol thingie" at the top of the left column. The left column is full of liquid all the way up to that triangular "symbol thingie." Above that point there is air at atmospheric pressure, but below that point there is liquid. Were you aware of that?
I am guessing at this point to move onto the tank? If so, a 6.7m head factored into my rho * g * h equation then gives me the pressure at the interface inside the tank?