When the water dries it leaves the de.
BTW you guys are all fen crazy! Using a fogger in flower shits fucken poisen. I havent seen a fogger that wasnt poisen and i ran a grow shop for years. DE earth tasts like shit when its burnt. Hope you didnt get your spray on the flowers. Even most of the products that are safe are oil based and leave a resadue. The only product i have found that dosnt alter flavor and is safe to use even the day of harvest is Nuke Em by flying skull.
In veg use whatever but be carefull with your flowers.