I put Heed in my camelbak about 2 years ago and ended up replacing the bladder because of mold growth. I never ever put anything in the camelbak but plain water. I put Heed in my polar bottles and take along a ziploc bag of extra heed to add to the bottle as needed. I can't remember if I didn't clean out the bladder till the next day or what but had mold growth pretty quick.