Is there a formula for antifreeze

I bought my MGbgt from Alberta...it had 2 block heaters !

@ 2 winters ago, we had neg 30s w/o the windchill but the coldest place I have ever lived was Ottawa..it is a wet cold...we had a car heater that clicked on about 4:30 in the morning..we we got into the car at 7, the seats would be like plywood..

I have a tester..new concentrate antifreeze and a day w/o snow...what more could I ask for :)

Thanks all..I tell you how mush I added..

Ian