diff --git a/pumpingStation.html b/pumpingStation.html
index 8c56986..6103316 100644
--- a/pumpingStation.html
+++ b/pumpingStation.html
@@ -24,6 +24,7 @@
       heightInlet:    { value: 0.8 }, // m, centre of inlet pipe above floor
       heightOutlet:   { value: 0.2 }, // m, centre of outlet pipe above floor
       heightOverflow: { value: 0.9 }, // m, overflow elevation
+      minHeightBasedOn: { value: "outlet" }, // basis for minimum height check: inlet or outlet
 
       // Advanced reference information
       refHeight:      { value: "NAP" }, // reference height
@@ -86,6 +87,10 @@
         refHeightEl.value = this.refHeight || "NAP";
       }
 
+      const minHeightBasedOnEl = document.getElementById("node-input-minHeightBasedOn");
+      if (minHeightBasedOnEl) {
+        minHeightBasedOnEl.value = this.minHeightBasedOn;
+      }
 
         //------------------- END OF CUSTOM config UI ELEMENTS ------------------- //
     },
@@ -98,6 +103,7 @@
 
       //node specific
       node.refHeight = document.getElementById("node-input-refHeight").value || "NAP";
+      node.minHeightBasedOn = document.getElementById("node-input-minHeightBasedOn").value || "outlet";
       node.simulator = document.getElementById("node-input-simulator").checked;
 
       ["basinVolume","basinHeight","heightInlet","heightOutlet","heightOverflow","basinBottomRef"]
@@ -151,6 +157,13 @@
   <hr>
 
   <!-- Reference data -->
+  <div class="form-row">
+    <label for="node-input-minHeightBasedOn"><i class="fa fa-arrows-v"></i> Minimum Height Based On</label>
+    <select id="node-input-minHeightBasedOn" style="width:60%;">
+      <option value="inlet">Inlet Elevation</option>
+      <option value="outlet">Outlet Elevation</option>
+    </select>
+  </div>
   <div class="form-row">
     <label for="node-input-refHeight"><i class="fa fa-map-marker"></i> Reference height</label>
     <select id="node-input-refHeight" style="width:60%;">
diff --git a/src/nodeClass.js b/src/nodeClass.js
index 3d1c376..f6b6a0f 100644
--- a/src/nodeClass.js
+++ b/src/nodeClass.js
@@ -63,6 +63,7 @@ class nodeClass {
       },
       hydraulics:{
         refHeight: uiConfig.refHeight,
+        minHeightBasedOn: uiConfig.minHeightBasedOn,
         basinBottomRef: uiConfig.basinBottomRef,
       }
     };
@@ -191,13 +192,9 @@ class nodeClass {
     this.node.on('input', (msg, send, done) => {
       switch (msg.topic) {
         //example
-        /*case 'simulator':
-          this.source.toggleSimulation();      
+        case 'changemode':
+          this.source.changeMode(msg.payload);
           break;
-        default:
-          this.source.handleInput(msg);
-          break;
-          */
         case 'registerChild':
           // Register this node as a child of the parent node
           const childId = msg.payload;
diff --git a/src/specificClass.js b/src/specificClass.js
index b179014..508c8d2 100644
--- a/src/specificClass.js
+++ b/src/specificClass.js
@@ -106,7 +106,7 @@ class PumpingStation {
     //get threshholds from config
     const timeThreshhold = this.config.safety.timeleftToFullOrEmptyThresholdSeconds; //seconds
     const triggerHighVol = this.basin.maxVolOverflow * ( this.config.safety.overfillThresholdPercent/100 );
-    const triggerLowVol = this.basin.minVolOut * ( this.config.safety.dryRunThresholdPercent/100 );
+    const triggerLowVol = this.basin.minVol * ( this.config.safety.dryRunThresholdPercent/100 );
 
     // trigger conditions for draining
     if(direction == "draining"){
@@ -165,10 +165,10 @@ class PumpingStation {
   }
 
   changeMode(newMode){
-
     if ( this.config.control.allowedModes.has(newMode) ){
+      const currentMode = this.mode;
+      this.logger.info(`Control mode changing from ${currentMode} to ${newMode}`);
       this.mode = newMode;
-      this.logger.info(`Control mode changed from ${currentMode} to ${newMode}`);
     }
     else{
       this.logger.warn(`Attempted to change to unsupported control mode: ${newMode}`);
@@ -176,48 +176,6 @@ class PumpingStation {
 
   }
 
-  /* old levelcontrol
-  async _controlLevelBased(snapshot, remainingTime) {
-
-
-    // current volume as a percentage of usable capacity
-    const vol = this._resolveVolume(snapshot);
-    if (vol == null) {
-      this.logger.warn('No valid volume found for level-based control');
-      return;
-    }
-
-    const { thresholds, timeThresholdSeconds } = this.config.control.levelbased;
-    const percentFull = (vol / this.basin.maxVolOverflow) * 100;
-
-    // pick thresholds that are now crossed but were not crossed before
-    const newlyCrossed = thresholds.filter(t => percentFull >= t && !this._levelState.crossed.has(t));
-    this.logger.debug(`Level-based control: vol=${vol.toFixed(2)} m³ (${percentFull.toFixed(1)}%), newly crossed thresholds: [${newlyCrossed.join(', ')}]`);
-    if (!newlyCrossed.length) return;
-
-    const now = Date.now();
-    if (!this._levelState.dwellUntil) {
-      this._levelState.dwellUntil = now + timeThresholdSeconds * 1000;
-      this.logger.debug(`Level-based control: waiting ${timeThresholdSeconds}s before acting`);
-      return;
-    }
-
-    this.logger.debug(`Level-based control: dwelling for another ${Math.round((this._levelState.dwellUntil - now) / 1000)} seconds`);
-    if (now < this._levelState.dwellUntil) return; // still waiting
-
-    this._levelState.dwellUntil = null; // dwell satisfied, let pumps start
-
-    for (const threshold of newlyCrossed) {
-      const nextMachine = this._nextIdleMachine();
-      if (!nextMachine) break;
-      this._levelState.crossed.add(threshold);
-      this.logger.info(
-        `level-based control: threshold ${threshold}% reached, starting "${nextMachine.config.general.name}" (vol=${vol.toFixed(2)} m³)`
-      );
-      await nextMachine.handleInput('parent', 'execSequence', 'startup');
-    }
-  }
-*/
   async _controlLevelBased(snapshot, remainingTime) {
 
 
@@ -337,12 +295,19 @@ class PumpingStation {
       case "flowbased":
         this._controlFlowBased();
         break;
+      case "manual":
+        this._manualControl();
+        break;
       default:
         this.logger.warn(`Unsupported control mode: ${mode}`);
     }
 
   }
 
+  _manualControl() {
+    // Nothing to do - manual mode
+  }
+
   //calibrate the predicted volume to a known value
   calibratePredictedVolume(calibratedVol, timestamp = Date.now()){
 
@@ -835,17 +800,22 @@ class PumpingStation {
 
   initBasinProperties() {
 
-    const volEmptyBasin = this.config.basin.volume;
-    const heightBasin = this.config.basin.height;
-    const heightInlet = this.config.basin.heightInlet;
-    const heightOutlet = this.config.basin.heightOutlet;
-    const heightOverflow = this.config.basin.heightOverflow;
+    //is min height based on inlet or outlet elevation?
+    const minHeightBasedOn = this.config.hydraulics.minHeightBasedOn;
 
-    const surfaceArea = volEmptyBasin / heightBasin;
-    const maxVol = heightBasin * surfaceArea;
-    const maxVolOverflow = heightOverflow * surfaceArea;
-    const minVol = heightOutlet * surfaceArea;
-    const minVolOut = heightInlet * surfaceArea;
+    const volEmptyBasin = this.config.basin.volume; //volume when basin is empty
+    const heightBasin = this.config.basin.height; //total height of basin
+    const heightInlet = this.config.basin.heightInlet; //height at which inlet is located
+    const heightOutlet = this.config.basin.heightOutlet; //height at which outlet is located
+    const heightOverflow = this.config.basin.heightOverflow; //height at which overflow occurs
+
+    const surfaceArea = volEmptyBasin / heightBasin; //assume uniform cross section for now
+    const maxVol = heightBasin * surfaceArea; //maximum volume when basin is full
+    const maxVolOverflow = heightOverflow * surfaceArea; //maximum volume before overflow occurs
+    const minVolOut = heightOutlet * surfaceArea; //minimum volume to have outlet just above basin bottom
+    const minVolIn = heightInlet * surfaceArea; //minimum volume to have inlet just above waterline
+    const minVol = (minHeightBasedOn === "inlet") ? minVolIn : minVolOut;
+    this.logger.debug(`Basin min volume based on ${minHeightBasedOn} : ${minVol.toFixed(2)} m3`);
 
     this.basin = {
       volEmptyBasin,
@@ -856,11 +826,13 @@ class PumpingStation {
       surfaceArea,
       maxVol,
       maxVolOverflow,
+      minVolIn,
+      minVolOut,
       minVol,
-      minVolOut
+      minHeightBasedOn
     };
 
-    this.measurements.type('volume').variant('predicted').position('atEquipment').value(heightOutlet).unit('m3');
+    this.measurements.type('volume').variant('predicted').position('atEquipment').value(minVol).unit('m3');
 
     this.logger.debug(
       `Basin initialized | area=${surfaceArea.toFixed(2)} m2, max=${maxVol.toFixed(2)} m3, overflow=${maxVolOverflow.toFixed(2)} m3`
@@ -899,6 +871,8 @@ class PumpingStation {
     output.minVol = this.basin.minVol;
     output.maxVolOverflow = this.basin.maxVolOverflow;
     output.minVolOut = this.basin.minVolOut;
+    output.minVolIn = this.basin.minVolIn;
+    output.minHeightBasedOn = this.basin.minHeightBasedOn;
     return output;
   }
 }