SWG's and CL Shock

[iwannapool]

If you have a SWG and you find yourself in a position that you need to CL shock, say need to raise CL to 15-20 ppm, do you increase the demand on the SWG to do this or add bleach?

It would seem to me if you wanted to prolong the SWG life and cleaning you'd just pour some cheap bleach in.

What do people do?