just get it from a disease free system.
And one that is at least WS free for 6 weeks.
I normally give out. But you are a bit far...
also, you must acclimatize the new sand, especially in regards to temperature. Just float the cupful in a bag in your sump area until temp the same. Also add little bit of water every 5 minutes.
No point in getting new bacteria and giving them a death shock...