How to keep silken tofu fresh for 3 days in the fridge?

Our family love silken tofu a lot.  I buy tofu only once a week.  So the tofu has to stay fresh at least for 3 days.  I got this tip from my friend which I think is rather useful.

Procedure:

1. Pour away the water in the tofu container. 
2. Rinse the tofu with clean water.
3. Add 1 tsp salt to a container of water which just enough to cover the tofu.  Stir until salt is dissolved.
4. Submerge the tofu into it.  Make sure tofu is fully covered with the salt water.
5. Keep in the fridge chilled room.

Note: If tofu still smell 'sourish' rather than soy after 3 days, most likely the sarine is not salty enough, add a little bit more salt the next time.

It should work.  The tofu should be able to stay fresh for 3 days.  I know it because I usually consumed mine within 3 days.