How to specify the database to use?

[richb201]

I am using two databases; a local copy of mysql which works great with GC. I plan to use AWS' RDS Postgresql for the images for use with Image crud. I have opened two databases using:
$DB1 = $this->load->database('default', TRUE);
$DB2 = $this->load->database('postgres', TRUE);
Default is using the mysql and that works fine. How do I tell Image Crud to use $DB2 instead?