Can I blow out with air and be safe in Mi. winter.

[richard717]

I used my 5er for 2 extra weekends in Mi. needed to blow out water so as not to waste anti-freeze. I work at truck shop so I have air. I maded my own adpt. to blow out fresh water side of trailer, and will same adpt be able to blow out black tank flush line. Should I blow out the line to fill the fresh tank from the city water valve in the control center? I have a drain on the fresh tank in the back of trailer. Owner manual says pour anti-freeze into fresh tank. I have never poured anti-freeze into fresh tank. Is this a YES or NO? I have 2 clear lines coming into control center in basement with shut off valves on and going down through floor. Are these for my hot water by-pass? They had anti-freeze in them when I bought this unit in Aug.(first owner didn't use it last summer). Made mistake once not getting anti-freeze in(older trailer)before freeze, but got it inside asap, and saved a lot of heart ache. Thanks for the help.