I took a BPW34 photodiode with 240 ohms resistor in paralell and connected that to the tank level input. tank sensor type set to 30- 240ohms. diode cathode (the slightly wider pin) should go to the odd numbered tank level input of the venus GX. the other side to the odd pin +1 number. do not short the wires to any other wires , do not connect to ground. solar sensor.jpg