To Answer your question, probable just flush the entire system well, at least until the water quite foaming from the antifreeze. Then refill fresh water tank with chlorine bleach solution, let it sit overnight, then flush through all faucets, and drain completely. Unless there is blace stuff showing in your water lines, refill with clorinated city water and you are finished! Note that by having antifreeze in the fresh tank that long, the taste will be difficult to get rid of, and will probably take some time and a lot of water to get rid of. Its not harmful if you want to drink it, but is fine for washing and such.