Any one that goes deep enough. The question is, how deep?
GE Druck's PTX 1730 says it does up to 600m H2O with cables/vents up to 575m, although it isn't clear whether you need to measure 400m of water or the well happens to be 400m deep. Many times the measurement is 50m of water above the transmitter with the transmitter submersed only partially down the well.
In any event, a transmitter just produces a process variable (PV) signal; you need a controller (that uses the PV) to tell the pump when to turn on or off or how much to change speed, whatever.
Something I have done before was to make use of a submersible sensor and connect a 4mm steel cable to its cable to take up the stresses on the cable, although the manufacturer specified that the cable is strong enough to take the full weight for the length of cable but I wanted to make sure. The submersible sensor is basically just a small narrow tube shape DP transmitter and the vented LP leg is a small plastic tube that runs inside the cable so it is critical to look after this cable at all times to ensure that no sharp bends is done on it ever in order to protect this small plastic tube in the cable.
In my case the liquid was dirt and mud was involved so I installed the transmitter inside a small stainless steel box full of holes and pack the box full of nylon shade netting to try and prevent clogging of the sensor. It is still working today after four years in a very bad environment.
The type I used was a LH-10 from Wika but I am sure there are a lot of other companies that can supply something similar.
