The culture is the best course of action.

I use a 16 oz. bottle of Isopropyl alcohol, a tablespoon of boric acid and 10-12 drops of Genetian Violet. The alcohol serves as the carrier and readily evaporates. The boric acid lowers the PH and the Genetian Violet serves as a topical.

It is mixed in the alcohol bottle and a hole poked in the top to make a squirt bottle. Works wonders. EWO