I can't say what the flakes are, but with respect to borates. They can act as a buffer to pH change. I added them to my pool (I also have a swcg) and went from having to add acid weekly to having to add every two or three weeks. It does increase pH, so you have to add carefully and dose with lots of acid to keep pH from getting too high. Instructions for how to do it are here: http://www.poolforum.com/pf2/showthread.php?18597 . One thing to remember is that "making it resistant to pH change" goes both ways. You add acid less frequently, yes - but you end up putting larger doses in when it comes time to drop the pH back down. You spend about the same amount of money on acid, it's just less work to add acid less frequently.

Where do you have your SWCG output level set to (usually there is a knob to control the output level via limiting "on" time)? Also, check your swcg manual for a recommended CYA concentration. Mine wants the cya to be at 90ppm, and salt at 3200ppm (I didn't see a salt reading in your post). Make sure these are both at the recommended level for your SWCG, and hopefully you will be able to turn down the swcg's output - which will in turn increases the lifespan of the cell as well as reducing how quickly the pH rises.

Another cause of pH rise would be aeration from water features/returns etc. Do you have water features that aerate the water? Are your return eyes pointed up so they rifle the top of the water? If so, you may want to consider running the water feature less or pointing the return eyes a little more "down".

If that white stuff ends up being calcium (and I'm not saying it is, someone else will have to chime in there) then you probably also need to clean and maybe acid wash your cell. One thought I had; several times I have had pool toys and other stuff (clothing, etc) in the pool that was getting broken down. One time I fought with this pink semi slimy gross substance appearing in my pool that would not die when shocked. I spent hours scooping it out every day, and it turned out to be one of those "noodles" that my kids play with was getting old and breaking down. The material from the inside of it was actually separating from the noodle and floating around.