I mentioned it in a previous thread a bit ago, but I figured I'd start a new one to get everyones attention
Anyways, this stuff is packaged with most home-brewing kits to sterilize the equipment. It's potent stuff and will kill pretty much everything it comes in contact with, yet its not harmful to humans if kept in very small quantities (eg. if you use moms measuring cup to fill your system, just a good rinse with water is enough to make it safe to drink out of - at least when we make wine we only give a quick rinse to the bottles after we sterilize them and we haven't gotten sick/died yet). But I want to get the opinions of all you guys on the stuff before I put any in my system - learn all kinds of interesting things when you guys start discussing them eg. that Chlorine will cause the copper to oxidate faster (and yes, Chlorine was my first idea to keep growth down). So if anyone knows if it will affect copper/aluminum pipe/WB/rad/rez's, pumps, interact with water-wetter, etc. I'd like to hear it. We use vinyl tubing to syphon the wine (and so we sterilize the tubing) and it doesn't have any effect on that, so I doubt it will effect chem-grade Tygon either, dunno about silicon.
Anyways, the part you are all waiting for, the name of the stuff. Sodium Metabisulfate. It would take an incredibly small amount to sterilize an entire water cooling system, and keep it sterile. Should be able to go to any home-brewing supply store and get some of it (way more than you need, a small packet of the powder makes 4 liters if I remember right - I might have 1/4 of a liter of fluid in my system, but I don't have a res).