Conductivity Sensor Issue

Hello everybody,

I am trying to measure conductivity from liquids water, water with salt, sugar, etc. I am using a conductivity switch sensor SEN0223 from DFROBOT brand. I would like to know first: Is this board suppose to work like an EC sensor? If yes, then I am having this problem:

I always get the same conductivity readings on all the liquids I am using. My current project is like this:

– I created a probe by following a video on youtube. This probe has a pen barrel in which two copper wires are attached on opposite sides of the
barrel. The ends of the copper wire are wrapped with nichrome wire. Then the ends of the nichrome wire are connected to the SEN0223 board with alligators. Link of the video I saw is this one: https://www.youtube.com/watch?v=B0lrcvT2HRc.
– My circuit diagram is:
– VCC : connected to SV5
– GND to GND
– Signal connected to the Analog A0 pin
My Code is:
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(A0,INPUT);
pinMode(22,OUTPUT);
digitalWrite(22,HIGH);

}

void loop() {
// put your main code here, to run repeatedly:
float voltage = (analogRead(A0))*(5.0/1023);
Serial.println(“Conductivity = “);
Serial.println(voltage);
delay (500);
}
Link of the board:
https://wiki.dfrobot.com/Conductivity_Switch_Sensor_SKU__SEN0223

I am not so sure were is my problem exactly. Even if I am missing something like a conductivity equation, I will always get the same answer regardless because the analog read is always reading 5V. I do not if my circuit diagram is wrong either. I hope to hear someone soon! I will attach a picture of my project.