Your SWG will cause the pH to climb. You'll need to keep muriatic acid on hand to adjust.
Despite what your pool store may tell you, there is no such thing as "dry muriatic acid".
Dry acid, or "pH Down" powder has more junk you don't need.
Given that the SWG will continuously increase pH, you want to decrease it with a product that has the fewest side effects possible.
4.5FC is the lowest end of FC with CYA of 100. You want to get it up closer to 7, to give you a buffer until you empty/refill ~20% or so of your water (goal 80PPM CYA), after which time your MINIMUM FC should be around 3.6, but 5.5-6.0 would be desirable.
Your CC is still marginal.
If I were you, I'd change out 20% water (a good time to vac well to waste, backwash the filter really well, then pump down a little more, and top up) adjust pH to 7.2 and SLAM to kill off that last bit of CC. I'm guessing it would be a quick turn around, as it doesn't sound like you're in bad shape.