Back to the drawing board! I have been running a test with the new optical sensor leaving it immersed in fuel. For the first few days , no problem, but on todays inspection the fuel had clouded the polycarbonate lens, rendering its function useless for internally refracting the light.
There is probably a solution and that is a sensor with a polysulphone lens which is OK for fuel. The problem is the sensor is £30 instead of £7, which starts to make it unviable.
I will probably try it though.
