Help I Think My Plant Have Mold/fungus

i have recently started using a different method of growing and i dont know any1 else using this method. the plants are potted in a washing bowl with bigger then average drain holes the bowl is resting on a 15-20ltr tub witch is filled to were the bottom of the bowl ends their is a airator in the water with the pump the roots a growing into the water i am told that this way increases yealdbutthe problem is it also promotes mold/fungus and my plant still in the 1st wk of bud and the leaves have a white like dust on them what can i do to solve this problem

put a fan on it so the air is moving