I started seeing visible results after about 3-4 days, they were completely gone after 6 and I dosed 8 days just to make sure. Been dino free for about a month now! But still battling annoying Cyano (after having Dino's, I can live with a Cyano until it runs its course). I dosed mine in the morning, before the lights came on. Not that it mattered, but I went with the theory of hitting them when they are at their weakest. Good Luck!