Duck sound cure for dubious treatment (5,6)

I believe the answer is:

quack remedy

I'm a little stuck... Click here to teach me more about this clue!

'dubious treatment' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'duck sound cure' is the wordplay.
'duck sound' becomes 'quack' (I've seen this in another clue).
'cure' becomes 'remedy' (synonyms).
'quack'+'remedy'='QUACK REMEDY'

'for' is the link.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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