UUings

I just drained my Hotspring hot tub last night & turned it on, but it was late & I didn't add anything to the tub, except city water. This morning, the tub was at temperature, but when I opened the tub to add salt, the console was displaying the message "High Salt". Testing the water of course shows no salt. I drained the tub when it displayed the high salt message, figuring it was about time -- even though there had been little if any evaporation, but it was about time. (I did test the salt before & it was in the 1200 range. I also took a water sample to a spa place & they said it was 1400.) Help?