Chrissy,
I agree with Marty....
For now, you can just set the % of output to zero... With no salt, the cell will not try to produce chlorine, but what you do not want to have happen is for the cell to come on when the salt level is very high.. This can happen when the salt is first dumped in the pool, before it has had a chance to be diluted by the pool water..
If any of the cell's lights are on, when the pump is NOT running, your cell is not wired correctly.. If the flow switch fails, this can cause the cell to explode. While this does not happen often, it can and has happen, as reported here..
Thanks,
Jim R.