The Bible has been used in magical workings for a long time, this is not something new. Kabbalah practices and Hoodoo/Conjure works have used parts of the Bible as sources of power and instruction *long before* the invention of Wicca.
It is not just in Psalms or limited to the Old Testament either. Things can be found throughout the Bible. Here is a good article and starting point for those wanting to go through their Bible for potential works:
In regards to your work, there are no circles casted in hoodoo (or Christian Folk Magic as Connie calls it :P), so the addition of this is very unnecessary, especially since you claim the work is already for protection.
I'd go with a cleansing of the entire home and self (family if you can do that), call in the good, then I'd do a work for protection.
Psalm 69 I'd personally not use for protection. I can see this as a prayer for deliverance from your enemies, but nothing about this Psalm screams PROTECTION.