#define PH_PIN A0    // A0 pin

unsigned long int avgValue;
float b;
int buf[10], temp;

int f;
float val;
char buff2[10];
String valueString = "";
String Value = "";

void PH_Value(){
  for(int i=0; i<10; i++){
    buf[i] = analogRead(PH_PIN);
    delay(10);
  }

  for(int i=0; i<9; i++){
    for(int j=i+1; j<10; j++){
      if(buf[i] > buf[j]){
        temp = buf[i];
        buf[i] = buf[j];
        buf[j] = temp;
      }
    }
  }
  avgValue=0;
  for(int i=2; i<8; i++)
  avgValue+=buf[i];
  float phValue = (float) avgValue * 3.3/1024/6;
  phValue = 3.5 * phValue;
  Value = dtostrf(phValue, 4, 2, buff2);
  Serial.print("pH Value: ");
  Serial.print(Value);
  Serial.println("");
  valueString = "";
  delay(1000);
}

void setup() {
  Serial.begin(9600);
  delay(2000);
}

void loop() {
  PH_Value();
}