I use atmos 300. Mine was been frozen solid more times than I can count. When I boil it sets on top of the steam hood, and sometimes I will put it inside on the drip try to thaw it. For those of you that are using spray bottles of defoamer remeber that syrup travels toward defoamer, thats why they say if you are going to use it in the syrup pan to only use it in the partition closest to the draw off.