Debbie, I've noticed that every new cat I've brought in the house is messy in the litter box for the first week or so. We fostered a cat two summers ago and it was true for her too.

If you are going to continue adding baking soda one money saving suggestion is to go to a pool supply store and buy a big bag of soda from them. It's a lot cheaper than boxes from the grocery store. We buy it in 50 pound bags for around $20 because we use it in our swimming pool to increase the PH. I think in pool supply they call it sodium bicarbonate or something like that. Whatever it's chemical name is.