keshav_singh:
I have also found a pressure differential sensor - MPX 5010 DP – Differential Pressure SensorWhat is ur opinion on this one?
poor choice.
the pressure in the tube is based on the depth the tube is inserted in the fluid.
although most fluids are non-compressible, the way this works is that the air in the tube is compressed and Boyles law gives us the rules.
in a Fixed volume, an increase in termperature will create an increase in pressure.
your volume is not fixed, but an increase in temperature will result in the increase in air volume. this will effect readings, unless you calibrate for that temperature.
second, air is soluable in water so the volume of gas will reduce over time. this will result in the need to replace it.
typically, with a tube, one also adds air from a tiny orifice and the sensor style is called a bubblier, as you pump air to fill the tube and it bubbles out the bottom.
with this, you need to add an air pump. One pump for all tanks would work and you can get very tiny orifices 0.005" inches are common.