Currently building a site and need to create a 'Schedule' to display a Presenter that is on air at a particular time.

Using ACF plugin to enter a time that the presenter goes on air which saves the custom field value as a timestamp.

For some reason, I cant get the query to display the presenter that is on air at a certain time.  It seems to just show the presenter with the highest timestamp value when compared to the current time timestamp.  A simplified version of the code is below.

	<?php $args = array(
		'post_type' => 'presenter',
		'posts_per_page' => '1',
		'meta_key' => 'on_air',
		'orderby' => 'meta_value_num',
		'order' => 'DESC'

	);


	$airquery = new WP_Query( $args ); ?>

	<?php if ( $airquery->have_posts() ) : while ( $airquery->have_posts() ) : $airquery->the_post(); ?>

		<?php
			$now = strtotime(date('d-m-Y H:i:s')); // get current timestamp
			$stored_value = get_field('on_air');   // The saved post timestamp comparing to current timestamp
		?>

		<?php if( $now > $stored_value )
			{
				echo the_title();
			}
		?>

	<?php endwhile; endif; wp_reset_postdata(); ?>

As you can see, i'm querying the posts in the post type, and want to order by meta value, which also doesnt seem to be working.

All I get returned is the post with the greatest timestamp value above the current timestamp.

All very strange.  Dont know wether I need to somehow get the value of all the posts and then compare the `$stored_value` to the $now or not?

Any help would be great!