94,
You need to run your SWCG long enough to make the amount of chlorine your pool uses each day. This depends on the size of your SWCG and the size of your pool. It is not magic, it is math..
It make no sense to me, to run your pump if you are not making any chlorine, so this means the speed of your pump has to be fast enough to turn on the cell's flow switch.
The rest is up to you.
Another reason to run the pump is to skim your pools surface. Normally, the time it take to generate the chlorine you need is more that enough to skim your pool.
One option is to run the cell at 100% output and the pump for the shortest amount of time it takes to make the chlorine you need. This option is what someone with a single speed pump would want to do.
Another option is to run the cell at lowest possible output, but run the pump 24/7 at a low RPM.
A third option is anything in between.
I personally love running 24/7 at 1200 RPM, most of the time. This allows me to make a little chlorine all the time, and skim all the time. I've been doing this for over 10 years and doubt that I will ever go back to starting and stopping my pump each day. The cost to run 24/7 is less than $20 bucks a
month.
You will just have to experiment and figure out what works best for you.
Thanks,
Jim R.