Thank you all for your help,
Especially Mike and Myka. Your were on the money. The root cause was just what Myka said. When I took the unit out for a complete cleaning and upgrades, I checked the venturi. Just as Myka said the air intake in the venturi was blocked with salt/calcium. Clean that and now its is running great. In addition as Mike suggested I have now installed a valve on the inlet so I can control the inlet flow. Control of only the oultet can over pressure the skimemr leading to overflowing. Also I drilled and tapped the cup and installed a drain so if it does fill it will drain into a bucket and not over the floor. Thats a real plus for the wife
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So I hope this tread serves others in the future. This was a great learning. And I got to say I have a lot better understanding of what makes a HOB skimmer work. Still may in time go to a sump as I can see the advantages.
Once my tank settles down I will snap some picture to add to the tread as DIY upgrades for older HOB skimmers.