diff --git a/js/intro/view/IntroAnimator.js b/js/intro/view/IntroAnimator.js
index f47bc282..dd473370 100644
--- a/js/intro/view/IntroAnimator.js
+++ b/js/intro/view/IntroAnimator.js
@@ -32,7 +32,8 @@ export default class IntroAnimator {
 
     // Vertical position of system 1, instrumented for PhET-iO to support record/playback, see #53.
     const system1CenterYProperty = new NumberProperty( system1Node.centerY, {
-      tandem: tandem.createTandem( 'system1CenterYProperty' )
+      tandem: tandem.createTandem( 'system1CenterYProperty' ),
+      phetioReadOnly: true
     } );
     system1CenterYProperty.link( centerY => {
       system1Node.centerY = centerY;
@@ -41,7 +42,8 @@ export default class IntroAnimator {
     // Opacity of system 2, instrumented for PhET-iO to support record/playback, see #53.
     const system2OpacityProperty = new NumberProperty( system2Node.opacity, {
       isValidValue: value => ( value >= 0 && value <= 1 ),
-      tandem: tandem.createTandem( 'system2OpacityProperty' )
+      tandem: tandem.createTandem( 'system2OpacityProperty' ),
+      phetioReadOnly: true
     } );
     system2OpacityProperty.link( opacity => {
       system2Node.opacity = opacity;
diff --git a/js/intro/view/IntroScreenView.js b/js/intro/view/IntroScreenView.js
index 0fbcac9c..4d2171da 100644
--- a/js/intro/view/IntroScreenView.js
+++ b/js/intro/view/IntroScreenView.js
@@ -90,7 +90,7 @@ export default class IntroScreenView extends ScreenView {
 
     // @private Animates the transitions between 1 and 2 systems
     this.animator = new IntroAnimator( viewProperties.numberOfSystemsProperty, system1Node, system2Node,
-      this.layoutBounds, tandem );
+      this.layoutBounds, tandem.createTandem( 'animator' ) );
   }
 
   /**