Posted from another site:

i had a real bad run of probs with my dwc and an unkown bacteria. cluey old bloke put me onto ozone and i aint looked back. i run it twice a day for 10 mins on low setting. he recommended 3 x 5mins during lights on but my sytem is 150L or so.

Also many homes in asia use ozone to clean their food. they have the same ozone unit for hydro use under there kitchen sinks with an airstone that sits in the sink. they fill sink and wash all types of food in it before cookin.

peace
c