Model - AWN412SP111TW01

How much slack should be in the belt on this machine? This one seems awful loose. Complaint was no spin sometimes with large loads. There is belt debris indicating a worn belt for whatever reason. I intend to remove the belt to measure it (30 1/4" ?) and check the pump for any obstruction. There does not seem to be any adjustment on it, no sliders or anything, so I assume the tension/idler pulley comes into play here?