Yesterday my dad gave me a 5.5 cubic ft freezer that works great. The temperature setting dial is 1-5 (5 being the coldest). I've had it on 1 for 24hrs and a thermometer inside says +2F. That's pretty cold for the lowest setting but the freezer is completely empty. My question is, do I really need to go any colder than that when it's stocked? Is there a preferred temp to freeze at? Thanks.