do_action() hook into load-(page)

I have changed the do_action() for a apply_filter(). This worked as follows:

// Filter save settings
$settings = apply_filters( 'gtp_theme_settings_tab_save', $settings, $tab, $_POST );
$updated = update_option( 'gtp_theme_settings', $settings );  

And then my add_filter in plugin file looks like:

function ac_theme_settings_tab_save( $settings, $tab, $postdata ) {

    if( $tab == 'adcalls' ) {
        $settings['gtp_adcalls_domain_id'] = $postdata['gtp_adcalls_domain_id'];
    }
    return $settings;

}
add_filter( 'gtp_theme_settings_tab_save', 'ac_theme_settings_tab_save', 10, 3 );