Well, since this happened in Norway I used Norwegian washing soda which is also called Krystallsoda, and I assume it is because it is just white crystals. So, if you find a washing soda here that is in the form of white crystals I assume that would be kind to stay away from. And be aware not to stir around to get it mixed when you keep your promise not to do it.
This was however how I did what I should not have done.