Test the ceiling for asbestos if the house was built before 1980.

I use a pump-action sprayer tank to soak the popcorn before scraping it off.

You should probably apply knockdown joint compound texture to the ceiling, because under that popcorn you will find uneven joints--that's why popcorn was so popular with builders. If it's really bad, you may need to tape and smooth out the joints before applying texture.