I have a simple jQuery UI slider that has a numerical range from 25 to 35. It works fine and the default value is 28. I'm hoping to add a simple tick mark to the slider to indicate that 28 is where the default is. Is there a simple way to add an indicator?

$('#cycle_length').slider({
  range: "min",
  value: 28,
  min: 25,
  max: 35,
  step: 1,
  slide: function( event, ui ) {
    $( "#amount" ).val( ui.value );
  }
});
$( "#amount" ).val( $( "#cycle_length" ).slider( "value" ) );