I had a mold issue starting on the one tray that had seeds soaked in plain water with no added bleach. 2 gallons of rise water with about 1/4 cup bleach per gallon solved the problem. Had another tray that was starting to ferment (literally could smell alcohol) used the same treatment. Instantly gone. I should add i do rinse away the bleach water remaining about an hour later with about 2 gallons of water. -MCF