Goldfish in Big Tub

[Aquarium Freak]

Hi All my grandma has a pond with 5 goldfish in it. She has 5 of them varying from 5inch to 10inch. Heres the thing I live up in canada and in the winter her pond freezes through. So in the winter in they go to a 33g I know it's sad. But at least she has 2 pumps made for 50g's on it. But anyways I'm trying to tell her that is to small for the goldfish but she deosn't want to spend like $150 to buy like a 100g or soemthing. So I thought up this solution. Would it be o.k. if she bought like a big plastic tub almost like a water trough exept its round deeper and bigger. If we bought some more filteration for it could she winter them in it?
Sorry for such the long post but i just wanted to go into details
Also winters coming up pretty quick
Thanks

 

[Fluff]

Rubbermaid tubs is how I overwinter my fish and it works well.

 

[krap101]

theres 50 gallon tubs and like smaller ponds.