 
 const int pumpA =  P2_1; //Acid Pump
 const int pumpB = P2_2; //Base Pump
-const int Ex = P1_5; //Probe
+const int probe = P1_5; //Probe Pin
 const int pHS = 7;
-float T = 22 + 273;
-float Es = 1.5;
+float T = 22 + 273; // in Kelvin
+float Es = 1.5; // Not sure if this is in V or mV
 float pHX = 0;
 
 float calcX(float Ex);//this function calculate pH(X)


}

float calcX(float eX)
{
  float X;
  
  X = pHS + (((Es - Ex)*Faraday)/(R*T*ln10));
  
  return X;
}

  Serial.begin(9600);
  pinMode(pumpA, OUTPUT);  
  pinMode(pumpB, OUTPUT);
  pinMode(probe, INPUT); 
}
void loop()
{
  // read the probe value, the electric potential at pH measuring electrode
  // multiply by 0.0029 because it is  2.9 mV per unit of analogRead
  pHX = calcX(analogRead(probe) * (2.9/1000));
  
  //display on serial
  Serial.print("Standard pH is:  ");
