HI ziggy.. once yourr leaves look like that they don't recover (the plant can/will recover but the damage to the leaves is permenant)... so without new growth it can often be hard to tell if you fixed the problem..

You should probably have flushed for at least 24 hours..

It is a problem that your water is 200+ ppm straightout of the tap.. To tell you the truth, I am suprised you made it this far..

If you were growing Aeroponicaly you probably would not have made it this far...
Have you considered raising the PH to 6.5 for a few days...

if you can show us the entire plant..

I think you are going to be ok..

: )