Decided that since I'm going to change water every 3rd or 4th time I might add something to keep the bacteria and algae growth down..Athough I'm not sure what they would hurt? Its - "Humidifier Bacteriostatic®"...Haven't found anything that warns against using it in a hydroponic envirnment...?
I doubt that it would do anything in a hydro tank. Use hydrogen peroxide or bleach to keep root rot microbes at bay. I add 2 drops clorox per gallon daily, and have never had root rot.