Help WIth Restoring A Tank

Hello,

I was recently given a 130g acrylic tank that was used for saltwater.
It is in pretty bad shape.  It needs a good cleaning and smells pretty bad.

I removed the plumbing and hosed it out to remove all the loose junk.  The
algae and scale? are proving to be difficult to remove.  I have tried a
citrus cleaner, vinegar and a bit of elbow grease with little success.  I
have always had glass in the past but nothing near this size.

Any suggestions for me to get this back into shape would be appreciated.

Thanks