Could you please tell me whether the sentence bellow is correct or ...

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Feb 9, 2018 15:38 questions
Could you please tell me whether the sentence bellow is correct or not?
Our greatest asset is probably our swimming pool which at 25 metres isn't Olympic-sized, but now we've expanded it to eight lanes, it's much wider.
I think the word "at" is a little strange to be here. Could you please tell me whether it is correct or not? Thanks!