I think you need to increase your FC, not reduce it. If you look at the CYA/FC chart for a saltwater pool I think 4 or 5 is the Minimum you want to be not the target FC.
What I find is that the SWG setting is not a "Set it and Forget it" setting. I have to continually reset mine up or down depending on the time of year and the general weather conditions. If I set my SWG for an FC of 4 and then we have a couple of days of hot sunshine, my FC would easily sink below 3. (Although since we have not seen the sun in this part of Texas for a couple of weeks, I guess that is not something I'll have to worry about.)
I guess my point is, you should be keeping your FC two or three points higher that the minimum requirement.
Also.. is your CH really 50? That just does not sound right. I would think it would be in the 300 to 400 range.
Something else to watch at this point is your pH. I also run a pH of about 7.8, but I find that if my TA gets too much about 110 or 120 that my pH will move up to 7.9 to 8.0 if I don't take some action. I suggest you just record your readings and see what happens. It will give you feel for how your pool works.
Jim R.