I'm voting for "just add borates now". I fought and fought with the flakes starting just a few days after installing my SWG last year. I lowered my CH. I lowered my TA (which I couldn't really keep low because fill water was higher). I was dosing with acid every other day. I couldn't keep up. It was nerve wracking.
I ended up finally adding borates to 40 ppm and have not had one flake since. I also removed the SWG cell for winter and it was squeaky clean.
I still maintain my balance, because I obviously don't want other problems. I dose a quart of acid a week (sometimes 1/2 gal), and try to keep my CSI on the negative side.
Side note: before adding borates I noticed I had *more* flakes when the water was extra toasty. Yesterday I removed my solar cover because my water was over 93 degrees. Still no flakes.
Add the borates. You won't be sorry.
Side note #2: I don't know if this is a thing, or if it's all in my head, but my water seems silkier and more sparkly with the borates, bugs also don't seem to care for it much.
PS - I live in your area, so maybe there is something going on with our water
