Skimmer - noise issue

I'm running an Octopus skimmer that I got a few months back.  Does a great job removing skimmer.  I've recently had a noise issue develop that I'd like some thought/input on.
Last week I started to prepare my sump for adding some chaeto.  So, I moved the skimmer which had been sitting in the center of the sump to the right end of the sump - closer to where the water drains into the sump from the display tank.  The pump connects to the skimmer body via a 90 degree elbow.  The way I initially had the pump attached, the intake on the skimmer pump was close to the output from the skimmer itself.  So, as I moved the skimmer to the end of the tank, I also decided to turn the pump on the skimmer 180 degrees, so that the input for the skimmer pump directly faced where the water drains into the sump - it also meant that the output from the skimmer was further away from the input to the skimmer.  I thought this was a good idea for better getting the dirtiest water going into the skimmer.  Anyway with that change, the noise level on the skimmer increased significantly - not from the air tube (which I still have the silencer on), but from the water exiting the skimmer.  Now instead of having the water tumble nicely down the exit pipe of the skimmer, it's making about a 1/2 inch arch out of the tube and then falling into the sump.  Craziest thing.  I've tried raising and lowering the exit tube, but no difference.  Then every once in a while, the water tumbles instead of making the arch.  This morning I've turned the pump around again, and its quiet.  Don't know if that making any difference on performance though.  Anyone got any thoughts on this?????  I know alot of club members are using or have used an Octopus skimmer.

 

Thanks for the responses.   IaJim - I think you are right that it is somehow getting extra flow thru the skimmer due to the change in pointing the skimmer intake toward where the water enters the sump.  I don't think that the noise is due to just that it was disrupted because of the change - because as soon as I turned it around again so that it didn't face the drain into the sump, the noise went down immediately as the water was no longer coming so forcefully out of the skimmer output pipe.  So, I'm going to turn it around 180 degrees and see how that works.  And I've got a small round foam filter that will fit perfectly over/around the skimmer exit pipe (thanks for that idea Bill!)