Ok, i got a bong water cooler set up, but i need some sort of disinfectant to keep bacteria and fungus from growing in it. I'm using pvc pipe, copper waterblock, some brass fittings, clear plastic tubing, just basic stuff. need something cheap that won't corrode anything and won't evaporate and kill me or my dog. had bleach suggested. sodium bromide (i think it corrodes copper), and bromine (makes all hell break loose on pvc i think) were suggested already. any ideas would be appreciated. thanks