wow! if biofilm is calcium carb. related i wouldn't know what to say! i only got 2 that because of being non stop annoyed with carbon & then hearing from all of u bout it's purpose! it was beef stew juice that led me to the element! and heaps of other carbon compounds r they? i think. shows we all need to listen to our heads no matter what they may b saying.have 2 run, u save me so much effort!