I have made an ozone generator using a transformer from a small neon sign. I used to glass jars, putting the small glass jar inside of the big glass jar. With the two wires from the transformer I took some aluminum foil, folded it up and attached the wire to the foil and placed one wire inside the small jar. I did the same thing to the other wire but placed it in the larger jar so that when the transformer was turned on it would create an arc between the glass. This created ozone, then you would have to figure a way to get it into the water.