the cavitation could be caused by a number of issues. cavitation in the pump housing can destroy the impeller, btw. but if its the result of bubbles escaping the skimmer, there may be little yoou can do, except reduce the air being intaked into the becketts. one way you can check if its coming from the skimmer is to shut off the air intakes completely, and let it run in that state for a day or so. if the bubbles disapate in the tank, then you know the root cause of your problem. then your choices will be to either reduce the output of the pump, or reduce the air intake. just some ideas..... hth!
8)
mike s.
this method has been approved by 4 out of 5 voices in my head.