For the first time in 2 years, the dishwasher in my apartment is blinking for salt? I checked the model and apparently I have to fill it up with dishwasher salt. But when I tried to search online, it seems its not commonly available in NZ. Are there any alternatives? Do I really need to given that am assuming water in the city is not hard? Also the fact that the powder/tablet i use already comes with rinse aid?