salt level a bit high

[HAYMAN]

I salted my neighbors pool..............................added salt over a 6 hr period to a 3100 level. After that the pool"guy" added a shock treatment and some stabilizer. that night it went to 4100ppm. Why would that happen?
I did my own pool the same...without the extra chems and it stayed at 3100ppm. Will the 4100ppm level hurt the pool before we can get it down?

thanks