While you are shocking your pool, you need to brush your vinyl walls. Also, since you have an SWG the PH is always going to drift up. You will eventually be able to figure out a dosing strategy to keep the PH within operating parameters.

I would check the SWG thread to see if anyone talks about adding a small amount of muratic acid on a daily basis versus a lot at one time.

You may also have to make adjustments to your system to produce enough chlorine to keep FC between around 5 to 10 ppm constantly to keep algae from taking hold again based on your CYA level.

Good luck and brush those walls.