Your TA is fine at 80, If you pH isn't moving too quickly, I wouldn't worry about it.
I would add the rest of the CYA - you're still under 30.
You might want to bump your pH a bit with a little Borax ... but maybe not, do you find that you pH rises from using your SWCG?
You don't need to worry about CH in a vinyl pool - It's strange that your test doesn't work the way it should but ... I haven't done the CH test on my water 'cause it's meaningless to me. I suppose if my water was cloudy I might check.
Regarding the brown dust (and I don't know if this would help), I had a robot cleaner for three years I ran my Intex donut - it saved me hours as my yard is tree-covered. The filterbag is pretty fine - it might help - but $300 is a good price for one. It only lasted three years but I liked it so well I bought another this year.