Is this safe for my hermit ?

Two of my hermit recently died, and they made the entire cage smell terribly. I washed out the entire cage and it still has a fishy smell to it. All of my hermit seem active so i don't think one is dieing. I was wondering, would i be able to mix baking soda with sand to help future odors? Or can ingesting baking soda be harmful? Thanks in advance!