Arduino MEGA with USB - temp sensors halting

I have an Arduino Mega with the temperature sensors attached. I will be connecting it to Blynk via USB. The script below works fine and shows me the temperatures on the serial monitor every second…

    #include <Wire.h>
    #include <OneWire.h>
    #include <DallasTemperature.h>

    float tempC01, tempC02, tempC03;
    //////////// Temperature sensor start //////////// 

    // Data wire is plugged into port 12 on the Arduino
    #define ONE_WIRE_BUS_PIN 44

    OneWire oneWire(ONE_WIRE_BUS_PIN);
    DallasTemperature sensors(&oneWire);

    DeviceAddress Probe01 = { 0x28, 0x5E, 0x72, 0xC5, 0x06, 0x00, 0x00, 0xA4 }; 
    DeviceAddress Probe02 = { 0x28, 0x9F, 0x49, 0x2F, 0x06, 0x00, 0x00, 0xAA };
    DeviceAddress Probe03 = { 0x28, 0x7A, 0xFB, 0xC4, 0x06, 0x00, 0x00, 0x79 };

    //////////// Temperature sensor end //////////// 

    void setup() 
    {
      Serial.begin(9600); 
      
      // Initialize the Temperature measurement library
      sensors.begin();
      
      // set the resolution to 10 bit (Can be 9 to 12 bits .. lower is faster)
      sensors.setResolution(Probe01, 10);
      sensors.setResolution(Probe02, 10);
      sensors.setResolution(Probe03, 10); 
    }

    void loop() 
    { 
      sensors.requestTemperatures();  
      
      tempC01 = sensors.getTempC(Probe01);      // Tank 
      tempC02 = sensors.getTempC(Probe02);      // Sump
      tempC03 = sensors.getTempC(Probe03);      // LEDS
      
      
      Serial.print("Probe 1 (Tank) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC01));
      
      Serial.print("Probe 2 (Sump) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC02));
      
      Serial.print("Probe 3 (LEDS) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC03));
      Serial.println("----------------------");
      delay(1000);
    }

However this one below does not…

    #define BLYNK_PRINT Serial1

    #include <Wire.h>
    #include <OneWire.h>
    #include <DallasTemperature.h>

    #include <BlynkSimpleStream.h>
    char auth[] = "65b59e****************************5f4166";
    #define PIN_UPTIME V5

    float tempC01, tempC02, tempC03;
    //////////// Temperature sensor start //////////// 

    // Data wire is plugged into port 12 on the Arduino
    #define ONE_WIRE_BUS_PIN 44

    OneWire oneWire(ONE_WIRE_BUS_PIN);
    DallasTemperature sensors(&oneWire);

    DeviceAddress Probe01 = { 0x28, 0x5E, 0x72, 0xC5, 0x06, 0x00, 0x00, 0xA4 }; 
    DeviceAddress Probe02 = { 0x28, 0x9F, 0x49, 0x2F, 0x06, 0x00, 0x00, 0xAA };
    DeviceAddress Probe03 = { 0x28, 0x7A, 0xFB, 0xC4, 0x06, 0x00, 0x00, 0x79 };

    //////////// Temperature sensor end //////////// 

    BLYNK_READ(PIN_UPTIME)
    {
      // This command writes Arduino's uptime in seconds to Virtual Pin (5)
      Blynk.virtualWrite(PIN_UPTIME, millis() / 1000);
    }

    void setup() 
    {
      Serial.begin(9600); 
      Serial1.begin(9600);
      
      // Initialize the Temperature measurement library
      sensors.begin();
      
      // set the resolution to 10 bit (Can be 9 to 12 bits .. lower is faster)
      sensors.setResolution(Probe01, 10);
      sensors.setResolution(Probe02, 10);
      sensors.setResolution(Probe03, 10);
      
      Blynk.begin(Serial1, auth);
    }

    void loop() 
    {
      Blynk.run();
      
      sensors.requestTemperatures();  
      tempC01 = sensors.getTempC(Probe01);      // Tank 
      tempC02 = sensors.getTempC(Probe02);      // Sump
      tempC03 = sensors.getTempC(Probe03);      // LEDS
      
      Serial.print("Probe 1 (Tank) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC01));
      
      Serial.print("Probe 2 (Sump) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC02));
      
      Serial.print("Probe 3 (LEDS) = ");
      Serial.println(DallasTemperature::toFahrenheit(tempC03));
      Serial.println("----------------------");
      delay(1000);
    }

I have narrowed it down to this line which is what stops the sensors from returning results in Serial monitor…
Blynk.begin(Serial1, auth);

If you are connecting to Blynk Server via the USB link file, then you need to use Serial (the built in USB) for Blynk.begin() and Serial1 (pins 18, 19 on the MEGA) with a TTL-USB adapter for all other serial output

So I cannot run the serial output AND connect to Blynk via the normal USB lead?

No… that is normal for any serial port… one connection at a time.

Arrr ok I understand why it weren’t acting as I expected. I’ll try it again.