Replacing Live Sand

Hi All:
Happy New Year.

I have been trying to vacuum/siphon my sandbed more lately because of purple algae that is coming around.

I notice that I remove sand every time.

Is it permissible and safe to pt that sand back after I clean it? Or can I buy a bag of new live sand and add that without worrying about a new cycle?

Any thoughts/suggestions/techniques would be appreciated.