you aren't going to have a problem with bio balls yet. the tank is barely cycled. i would also suggest removing them, but they are not the source of nitrate yet. adding a substantial amount of rock will definitely change your parameters.
If you can't afford to do water changes, you may want to rethink the salt tank.
the chaeto stuffed in a bottle is not going to help anything. it's definitely not going to change parameters in a few days. remove the bio balls and put it in there with a light over top. use a mesh screen to stop it from traveling to the return pump and skimmer.