Not sure whether this will help you solve the noise ...
I'm using a H&S skimmer.
There was one time I took the needlewheel pump out for cleaning.
And after I put it back, I found it producing a rattling noise that was not present before.
Took me a few days of torment before I realise this ...
The two rubber thingys that are holding the ceramic shaft in the pump ... which fit into two holes on the pump chassis.
Make sure they are tightly inserted into their holes.
I use white tape to go around them before firmly pushing them in.
Peace at last ...