Changing default value for members per page

I am looking to return 120 members per page in my BuddyPress site's members listing, up from the default value of 20.

I would have thought that changing the file bp-core.php would do the trick. Like this:

function bp_core_get_users( $args = '' ) {
global $bp;

$defaults = array(
'type' => 'active', // active, newest, alphabetical, random or popular
'user_id' => false, // Pass a user_id to limit to only friend connections for this user
'search_terms' => false, // Limit to users that match these search terms

'include' => false, // Pass comma separated list of user_ids to limit to only these users
'per_page' => 120, // The number of results to return per page

However, nothing much happens, I still get 20 members listed per page:
http://mediajungle.dk/members

Am I overlooking/misunderstanding something?

Thanks!