Basically yes. You'll probably want to use a single supply capable OP with lower offset voltage than LM324.
To be able to always adjust the output zero, the second OP stage must have > 1 gain. I also think that you should use well calculated fixed instead of variable gain with a calibrated pressure sensor.
You have not described how that sensor will be physically connected in the tank. Remember that it is a differential pressure gauge. I believe P1 must be > than P2. Presumably, P2 will be connected to a known pressure, such as the atmosphere. That may be a given in your case. If so, I apologize, but there was another post in the past week where that factor was not considered.
better use a pressure sensor with the "AP" suffix instead of "DP"
they are already amplified, calibrated, and the output is from 0 to 5v linear...
just my 2 cts