For those of you without electricity at your troughs this does work.
I've been doing it for months.
Even did a little experiment today.
I left 2 troughs without jugs, and put jugs in 3 troughs.
Those with jugs were still completely unfrozen tonight.
Those without had a solid layer I had to break up.
It's easy! Just take old milk jugs (or water gallon jugs or restaurant frier oil jugs) and put some salt in them.
I did 5 tablespoons of rock salt in each and a small amount of water, then stick them in the trough!
I use 2 per as it keeps them moving more and creates less of a surface for ice to form.
What I've found is that during the day in full sunshine this keeps your troughs frost free down to 25 degrees F, and probably about 30 degrees F at night.
Over night temps last night were 9 degrees F and I did have a thin layer of ice but it was VERY thin, less than 1/2 an inch.
I am in normal temp and am definitely NOT guaranteeing this for everyone, it has just worked for me over the past couple months in our range of temps!
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