realize that the CSI is just a guide and that a range of values is accdptable. Also, running a salt pool on the slightly agressive side is probably a good idea since it will help prevent cell scaling. Too much stock is put into saturation indecies. They are only guides yet the are treated like religions! In terms of agressive vs scaling water pH is the primary factor to look at. Since SWGs do cause a pH rise the numbers I gave include a 'saftety factor' for the inevitable pH rise that will occur.
I've said it to you before and I will say it again, you are overthinking things and making them more comlicated than they need to be. You also don't have as good an understanding of pool chemistry as you think you do as evidenced by your post on Omni's granular triclor. You have latched on to Richard's spreadsheet as if it were handed down on the mount from a burning bush. Remember, it is stricty theorectical and Richard and I have discussed theorectical vs real world results in depth on numerous occasions. I am not discounting it's usefulness BUT other factors do come into play so it should merely be a guide, not a rigid set of rules for pool care.

You said :
"From my real life experience and that of my friend a FC of 4, pH of 7.6 or above, and a CyA of 70 guarantees one black algae at least where we live, especially in our old plaster pools."
Was this with a SWG or was the pool manually chlornated and if so, how? It does make a difference.