Many thanks for the reply! Since I'd had success with my prior method I'll disregard the pool shop guy and go with what's worked before. Good thing I didn't tell him I use bleach for shock! I plan to use the Pool Calculator to blast to about 15 ppm till the algae is/are gone, then rely on the SWG for maintenance.

As far as the pool store's method I have other things to do...photography, cooking, bee keeping, etc.