Reef Octopus 3000 SS pump appears to be surging

I recently purchased a reef octopus 3000 Super Space Saver. It has been surging since I purchased the unit. I have the equipment arranged so the output of the skimmer is above the water line in the sump by about 1/2 inch. Thinking I might have clogged the airline I also recently rinsed out the line with regular RO water. I still seem to have a problem with the skimmer surging which is playing havoc with my ATO unit.

Can you please help solve this issue. I think the skimmer is a great protein skimmer but I am disappointed that I am unable to maintain a constant head of foam in the unit and the resulting effect on the rest of the sumps operation.

Thanks,
Dave