I don't fire up my shallow diffusers until the ice is on. I have waited until the ice was 3-4" thick before running. It will open a hole in short order.

I tend to go by the depth of snow cover on the ice, the quality of ice itself, and the expected duration of ice cover as determining factors. I don't think I have ever ran the system to prevent ice cover, only to open a hole once it's already locked up.

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.