Quote Originally Posted by glbeas
You can get some pretty good sodium carbonate by looking for plain Washing Soda at the grocery store. You may have to make some mods due to a different hydrate content, I think it has more. That was covered in a previous thread.
I've been using Arm & Hammer Washing Soda to replace sodium carbonate at a 1 to 1 ratio. I've come to understand the A&H is monohydrated in the store bought variety. Just be sure it does not contain any perfumes or "brighteners" and you won't know any difference. Been using it for over a year and haven't found a problem.