yup, plain old, store-bought Hydrogen Peroxide 3% ... it will not hurt your plant (and, you said your plant is a 'goner') :wtf: ... one of the reasons hydroponics produce fast growth, isn't just because of the available nutrients, but also because of oxygen to the root system ... being constantly wet, cuts off the oxygen, and molds, fungi, etc., are free to develop ... H2O2 is an oxidizer, not only kills off the bacteria (both beneficial and harmful bacterias), but gives an oxygen boost to your roots ... after the bad things are killed, they should be replaced with beneficial bacteria, I like Fox Farm Big Bloom, but there are other fine ones, too ... I don't like rockwool, pH issues, and holds too much water, IMHO ... I can't help ya with ebb&flow, but that just sounds too wet, from my inexperienced mind, just a thought ... good luck ... :smokin: