diff --git a/.github/actions/spelling/expect.txt b/.github/actions/spelling/expect.txt
index 429f53ae0..080d8c9f2 100644
--- a/.github/actions/spelling/expect.txt
+++ b/.github/actions/spelling/expect.txt
@@ -29,6 +29,7 @@ emoji
 endif
 endl
 EVT
+EZO
 FONTFAMILY
 FONTSTYLE
 FONTWEIGHT
@@ -46,6 +47,7 @@ ifdef
 ine
 ino
 iostream
+isdigit
 isnan
 itoa
 jgfoster
diff --git a/examples/TankController/TankController.ino b/examples/TankController/TankController.ino
index e2c44a32b..205a7f3fa 100644
--- a/examples/TankController/TankController.ino
+++ b/examples/TankController/TankController.ino
@@ -8,6 +8,14 @@
 
 TankControllerLib *tank;
 
+void serialEvent() {  // if the hardware serial port_0 receives a char
+  tank->serialEvent();
+}
+
+void serialEvent1() {  // if the hardware serial port_1 receives a char
+  tank->serialEvent1();
+}
+
 void setup() {
   tank = TankControllerLib::instance();
   tank->setup();
diff --git a/scripts/install_libraries.sh b/scripts/install_libraries.sh
index 999655fc3..67cb0237c 100755
--- a/scripts/install_libraries.sh
+++ b/scripts/install_libraries.sh
@@ -22,54 +22,63 @@ fi
 # add missing libraries
 export GITHUB="https://github.com/Arduino-CI"
 if [ -d "./Adafruit_BusIO" ]; then
+  echo update Adafruit_BusIO
   (cd Adafruit_BusIO; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/Adafruit_BusIO.git
 fi
 
 if [ -d "./Adafruit_MAX31865" ]; then
+  echo update Adafruit_MAX31865
   (cd Adafruit_MAX31865; git pull)
 else
   git clone $SHALLOW_MAIN $GITHUB/Adafruit_MAX31865.git
 fi
 
 if [ -d "./Ethernet" ]; then
+  echo update Ethernet
   (cd Ethernet; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/Ethernet.git
 fi
 
 if [ -d "./LiquidCrystal" ]; then
+  echo update LiquidCrystal
   (cd LiquidCrystal; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/LiquidCrystal.git
 fi
 
 if [ -d "./RTClib" ]; then
+  echo update RTClib
   (cd RTClib; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/RTClib.git
 fi
 
 if [ -d "./Keypad" ]; then
+  echo update Keypad
   (cd Keypad; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/Keypad.git
 fi
 
 if [ -d "./Arduino-PID-Library" ]; then
+  echo update Arduino-PID-Library
   (cd Arduino-PID-Library; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/Arduino-PID-Library.git
 fi
 
 if [ -d "./Arduino-PID-AutoTune-Library" ]; then
+  echo update Arduino-PID-AutoTune-Library
   (cd Arduino-PID-AutoTune-Library; git pull)
 else
   git clone $SHALLOW_MASTER $GITHUB/Arduino-PID-AutoTune-Library.git
 fi
 
 if [ -d "./SD" ]; then
+  echo update SD
   (cd SD; git pull)
 else
   git clone $SHALLOW_MAIN $GITHUB/SD.git
diff --git a/src/Devices/PHProbe.cpp b/src/Devices/PHProbe.cpp
new file mode 100644
index 000000000..c1fdc0021
--- /dev/null
+++ b/src/Devices/PHProbe.cpp
@@ -0,0 +1,43 @@
+#include "Devices/PHProbe.h"
+
+#include "Devices/Serial_TC.h"
+
+//  class instance variables
+/**
+ * static variable for singleton
+ */
+PHProbe *PHProbe::_instance = nullptr;
+
+//  class methods
+/**
+ * static member function to return singleton
+ */
+PHProbe *PHProbe::instance() {
+  if (!_instance) {
+    _instance = new PHProbe();
+  }
+  return _instance;
+}
+
+//  instance methods
+/**
+ * constructor (private so clients use the singleton)
+ */
+PHProbe::PHProbe() {
+  Serial1.print(F("*OK,0\r"));  // Turn off the returning of OK after command to EZO pH
+  Serial1.print(F("C,1\r"));    // Reset pH stamp to continuous measurement: once per second
+}
+
+/**
+ * data arriving from probe
+ */
+void PHProbe::serialEvent1() {
+  String string = Serial1.readStringUntil(13);  // read the string until we see a <CR>
+  Serial_TC *serial = Serial_TC::instance();
+  if (string.length() > 0 && isdigit(string[0])) {  // if the first character in the string is a digit
+    value = string.toFloat();  // convert the string to a floating point number so it can be evaluated by the Arduino
+    serial->print(F("pH = "), false);
+    serial->print(value, 3);
+    serial->println();
+  }
+}
diff --git a/src/Devices/PHProbe.h b/src/Devices/PHProbe.h
new file mode 100644
index 000000000..5a54fd03e
--- /dev/null
+++ b/src/Devices/PHProbe.h
@@ -0,0 +1,19 @@
+#pragma once
+#include "Arduino.h"
+
+class PHProbe {
+public:
+  static PHProbe* instance();
+  double getPH() {
+    return value;
+  }
+  void serialEvent1();
+
+private:
+  // Class variable
+  static PHProbe* _instance;
+  // instance variable
+  double value = 0;
+  // Methods
+  PHProbe();
+};
diff --git a/src/TankControllerLib.cpp b/src/TankControllerLib.cpp
index 39219b4ec..6751aef2f 100644
--- a/src/TankControllerLib.cpp
+++ b/src/TankControllerLib.cpp
@@ -2,6 +2,7 @@
 
 #include "Devices/Keypad_TC.h"
 #include "Devices/LiquidCrystal_TC.h"
+#include "Devices/PHProbe.h"
 #include "Devices/SD_TC.h"
 #include "Devices/Serial_TC.h"
 #include "TC_util.h"
@@ -85,6 +86,20 @@ void TankControllerLib::loop() {
   handleUI();
 }
 
+/**
+ * This public instance function is called when there is data on the serial port(0).
+ */
+void TankControllerLib::serialEvent() {
+}
+
+/**
+ * This public instance function is called when there is data on the serial port(1).
+ * This the Atlas EZO pH circuit probe.
+ */
+void TankControllerLib::serialEvent1() {
+  PHProbe::instance()->serialEvent1();
+}
+
 /**
  * Set the next state
  */
diff --git a/src/TankControllerLib.h b/src/TankControllerLib.h
index 3699c8ccd..acd053f25 100644
--- a/src/TankControllerLib.h
+++ b/src/TankControllerLib.h
@@ -15,6 +15,8 @@ class TankControllerLib {
 
   // instance methods
   void loop();
+  void serialEvent();
+  void serialEvent1();
   void setNextState(UIState* newState, bool update = false);
   void setup();
   const char* stateName();
diff --git a/test/PHProbeTest.cpp b/test/PHProbeTest.cpp
new file mode 100644
index 000000000..d3aff4110
--- /dev/null
+++ b/test/PHProbeTest.cpp
@@ -0,0 +1,32 @@
+#include <Arduino.h>
+#include <ArduinoUnitTests.h>
+
+#include "Devices/PHProbe.h"
+#include "TankControllerLib.h"
+
+unittest(singleton) {
+  PHProbe *singleton1 = PHProbe::instance();
+  PHProbe *singleton2 = PHProbe::instance();
+  assertEqual(singleton1, singleton2);
+}
+
+unittest(constructor) {
+  assertEqual("*OK,0\rC,1\r", GODMODE()->serialPort[1].dataOut);
+}
+
+// tests getPH() as well
+unittest(serialEvent1) {
+  GodmodeState *state = GODMODE();
+  state->reset();
+  PHProbe *pPHProbe = PHProbe::instance();
+  assertEqual(0, pPHProbe->getPH());
+  GODMODE()->serialPort[1].dataIn = "7.75\r";  // the queue of data waiting to be read
+  TankControllerLib *pTC = TankControllerLib::instance();
+  state->serialPort[0].dataOut = "";
+  assertEqual("", state->serialPort[0].dataOut);
+  pTC->serialEvent1();
+  assertEqual("pH = 7.750\r\n", state->serialPort[0].dataOut);
+  assertEqual(7.75, PHProbe::instance()->getPH());
+}
+
+unittest_main()