I just mixed up 50 gallons of saltwater, and when I looked in the trash can, I saw brown film junk floating on the water. When i stirred it up, it would seperate and then kinda form back together on the top. The salt I used was somewhat moist even though it is kept sealed, but it looked very clean. The trash can had uncirculated saltwater sitting in it for about 3 months, but i rinsed it out what i thought to be pretty good. It was dark and i didnt look inside of it though. Maybe it is junk that collected on the inside of the can and didn't wash off...? Anyways, I netted most of it out because I don't want to waste 50gallons worth of salt and 50gallons worth of distilled water. Believe me...pushin that much water through wally world is no fun. any ideas?