Crossword Genius

Tallyman popular when going upstream (14)

Ross

I believe the answer is:

countercurrent

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

'when going upstream' is the definition.
I can't tell whether this defines the answer.

'tallyman popular' is the wordplay.
'tallyman' becomes 'counter' (I can't justify this - if you can you should believe this answer much more).
'popular' becomes 'current' (I've seen this before).
'counter'+'current'='COUNTERCURRENT'

Can you help me to learn more?

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