Steve gave you the right answer, shock once per week. If you are using dichlor, you should use approximately 6 or 7 times the amount that you use after each soak. So for example, if 1 teaspoon after soak gives you 3-5 ppm 15 minutes after adding it, then for shock you should add approximately 2 tablespoons plus 1 teaspoon. This may be somewhat conservative, but it is safe.
Regards,
Bill