Calfo Overflow Problem?

[SkiFletch]

Yes, that is also likely part of your problem

 

[Phoenixfish]

Yes, that is also likely part of your problem

just an earlier point i think BigC made, although ive not used plastic chains, i think they work by stopping the water creating a spinning vortex as it goes down the tube, stopping them from drawing excessive air along with the water which is one of the reasons why it can be noisy.