Miklos Tube

These are the components I used for my replication of Miklos's tube experiment. I half melted the poly water pipe and crimped the end. It is airtight on one end.
A small spring holds the needle in place on the end of a piece of threaded rod.
When assembled, the foam block (polystyrene) keeps the rod in the centre of the pipe

Here it is, fully assembled. Another piece of polystyrene plugs the end of the pipe like a cork.

Setting the tube on the end of a balance beam with a sharp pin for at the centre of gravity (for a bearing) and turning on my High Voltage (DC) power supply resulted in movement in the direction Miklos said it would! In the photo above, the balance-beam turned anti-clockwise

Some smoke soon found leaking corona discharge was blowing the balance beam.

The arrows show where the problems were - discharge from the connection on the lower right of the photo and a considerable amount of ion wind blowing from the end of the threaded rod, forcing the balance beam to turn anti-clockwise.

Simply insulating the electrical connection on the bottom right of the image stopped corona there, but how to stop any discharge from the threaded rod?

The answer was to cover the ends of the tube with large metal spheres.

Another smoke test revealed no corona discharge from either end of the tube.

After I covered the ends of the tube with metal spheres there should be no movement.

There was no corona discharge, but it still moved.

And it moved even quicker!

What the hell's going on here?

Help!