Do I need biocide if I use distilled water?

[ML Infamous]

lol thanks guys, I will probably go for iodine, guessing its cheaper then all other alternatives.. Anyone know if i can use a silver coin instead? I've got a few, maybe I can use a silver dime?

Silver Dimes (1964 and Earlier) are in the 90% silver area.

Not sure how well it would work, but I think if you had a few of them it would be fine, I could be wrong,