Bernoulli's equation - finding the pressure at the top of a tube

[Sigma Rho]

Here's my problem:-

A horizontal tube has a T-junction with a vertical tube coming downwards into a container of liquid, at height h below the T-junction. Air is forced into the horizontal tube which causes a pressure difference which sucks the liquid up the vertical tube.

What is the pressure at the top of the vertical tube?

I have the answer as
P = Po - 1/2 * /rhoA * v^2

where:
P = pressure at top of vertical tube
Po = atmospheric pressure
/rhoA = density of air in tube
v = velocity of air in tube

but I can't seem to derive this equation from Bernoulli's equation. (Or anything else! )

Any ideas?

Thanks.

 

[Sigma Rho]

s'okay, I've just worked it out. It was embarassingly simple!