I think you need to run your pump 100% of the time when you have a sock of CYA in the skimmer. Also if you give the sock a good squeeze every fifteen minutes you will likely get all the CYA disolved in three or four hours. I use one of my wife's old, calf length, nylon stockings and it works great, you can see exactly how much is left in the sock.
Also it's best if your pump is running when you take water samples for testing.
What do your timers look like? Is it possible one runs the pump on high speed and the other runs it on low speed? You may be able to manually switch each timer so it turns on and you can see what happens to the pump and the SWG. For now make sure you don't switch both timers on at the same time.
If you can't figure out how your timers work look for the Make and Model number and try to download the instruction manual from the internet.