Can I just add iodized salt to my meals instead of taking potassium iodide?

No, I wouldn't. Because you don't really know how much potassium iodide you're really getting when you're adding salt to your meals. Plus, if you add it to your meals when you're cooking, you lose some of the potassium iodide. So it's variable. And you want to make sure you're consistently getting potassium iodide every day. And the best way to know you're definitely getting enough is by taking a supplement with the right amount.