Neptune 3 Pro dual z rod belt tension

Hey all,
So I am trying to figure out why we have bad z wobble (or binding or whatever). I havent pulled the zrods off yet to see if they are bent, but I noticed the timing belt is pretty loose. Looks like i can push the belt out about 15mm or so. The top zrod mounts are kind of loose. Is that normal? I cant seem to find if there needs to be tension on it or how to tension it. Is this normal?