Food Grade VS Agricultural Grade

[rayjay]

I have been buying Dowflake and sometimes General's calcium chloride for many years and it's technical grade, the same grade as the calcium hydroxide that I've been using for many more years in my tanks as limewater for replacing evaporated water.
I have never seen agricultural grade chemicals so perhaps they mean technical grade.
The technical grade calcium hydroxide I purchase comes from the farm co-op that sells it to farmers to use as a disinfectant on the barn floors.