diff --git a/Part2_Central_board/Firmware/CentralUnit/CentralUnit.ino b/Part2_Central_board/Firmware/CentralUnit/CentralUnit.ino
index c22eebc..1e51b29 100644
--- a/Part2_Central_board/Firmware/CentralUnit/CentralUnit.ino
+++ b/Part2_Central_board/Firmware/CentralUnit/CentralUnit.ino
@@ -1,3 +1,4 @@
+#include <EEPROM.h>
 #include "WiFi.h"
 #include "ESPAsyncWebServer.h"
 #include <esp_task_wdt.h>
@@ -7,6 +8,7 @@
 #include "Wire.h"
 
 #define WDT_TIMEOUT		20000
+#define EEPROM_SIZE		4
 
 AsyncWebServer server(80);
 int WiFi_status = WL_IDLE_STATUS; 
@@ -15,6 +17,7 @@ volatile uint32_t nFlowSensorCount_last = 0;
 
 char dbgBuff[4024] = {0};
 uint32_t dbgBuffPos = 0;
+float fImpulsePerML = 0;
 
 void IRAM_ATTR ISR_flowSensor() {
     nFlowSensorCount++;
@@ -40,6 +43,21 @@ void setup()
 
 	Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);
 
+	// EEPROM begin
+	EEPROM.begin(EEPROM_SIZE);
+
+	// Debug EEPROM before read
+	Serial.println("Before read: fImpulsePerML");
+	Serial.println((float)(fImpulsePerML),4);
+	
+	// Read flow value from EEPROM
+	fImpulsePerML = EEPROM.readFloat(0);
+	
+	// Debug EEPROM after read
+	Serial.println("After read: fImpulsePerML");
+	Serial.println((float)(fImpulsePerML),4);
+
+
 	// Configure WDT
 	Serial.println("Configuring WDT...");
 	esp_task_wdt_init(WDT_TIMEOUT, true); //enable panic so ESP32 restarts
@@ -273,6 +291,36 @@ void setupWebServer(void)
 		request->send(200, "text/plain", "OK");
 		return;
 	});
+
+	// Calibrate flow sensor
+	server.on("/calibrateFlowSensor", HTTP_GET, [] (AsyncWebServerRequest *request) {
+		Serial.println("Calibrate edges per mL");
+
+		if ( request->hasParam("edges") )
+		{
+			String xEdges;
+			float fEdges = 0;
+
+			xEdges = request->getParam("edges")->value();
+			fEdges = xEdges.toFloat();
+
+			// Update value
+			fImpulsePerML = fEdges;
+			EEPROM.writeFloat(0, fEdges);//EEPROM.put(address, param);
+			EEPROM.commit();
+
+			Serial.print("Changing fImpulsePerML to ");
+			Serial.println((float)(fImpulsePerML),4);
+
+			request->send(200, "text/plain", "OK");
+			return;
+		}
+		else
+		{
+			request->send(404, "text/plain", "MISSING_ARGUMENT");
+			return;
+		}
+	});
 }
 
 
diff --git a/Part2_Central_board/Firmware/CentralUnit/PlantSystem_MainLogic.ino b/Part2_Central_board/Firmware/CentralUnit/PlantSystem_MainLogic.ino
index 312140b..7c9f2a7 100644
--- a/Part2_Central_board/Firmware/CentralUnit/PlantSystem_MainLogic.ino
+++ b/Part2_Central_board/Firmware/CentralUnit/PlantSystem_MainLogic.ino
@@ -161,8 +161,8 @@ void PlantSystem_tick(void)
 		flowInterruptEnabled(true);
 		
 		// - Turn ON pump
+		bWateringError = true;
 		Serial.println("Turning pump ON");
-		delay(200);
 		digitalWrite(WATER_PUMP_EN_PIN, HIGH);
 
 		esp_task_wdt_reset();
@@ -170,31 +170,32 @@ void PlantSystem_tick(void)
 		
 		// Calculate water flow
 		uint32_t nWaterFlow_millis_timestamp = millis();
-		float flowRate = 0.0;
-		unsigned int flowMilliLitres =0;
+		float flowMilliLitres = 0.0;
 		unsigned long totalMilliLitres = 0;
 
+		// Wait until target mL or timeout is reached
 		while(millis() < nTimeout)
 		{
-			if((millis() - nWaterFlow_millis_timestamp) > 1000)    // Only process counters once per second
+			// Calculate mL every second
+			if( millis() >= nWaterFlow_millis_timestamp)
 			{
+				// Disable interrupts
 				flowInterruptEnabled(false);
 
-				nFlowSensorCount_last = nFlowSensorCount;
-				nFlowSensorCount = 0;
-				bWateringError = true;
-				
-
-				flowRate = ((1000.0 / (millis() - nWaterFlow_millis_timestamp)) * nFlowSensorCount_last) / WATERING_FLOW_EDGES_PER_L;
-				flowMilliLitres = (flowRate / 60) * 1000;
+				// Update mL
+				flowMilliLitres = nFlowSensorCount/fImpulsePerML;
 				totalMilliLitres += flowMilliLitres;
 
+				// Check if target has been reached
 				if(totalMilliLitres >= nWatering_volume)
 				{
+					bWateringError = false;
 					break;
 				}
-
-				nWaterFlow_millis_timestamp = millis();
+				
+				// Update for next iteration
+				nWaterFlow_millis_timestamp = millis() + 1000;
+				nFlowSensorCount = 0;
 				esp_task_wdt_reset();
 				flowInterruptEnabled(true);
 			}
@@ -221,7 +222,7 @@ void PlantSystem_tick(void)
 		bWatering_requestPending = false;
 		if(bWateringError)
 		{
-			LED_Blink(3, 250);
+			LED_Blink(4, 250);
 		}
 		else
 		{