FLEAS

I have heard that you can give a dog sulfur in his water and this will keep the fleas and ticks off them ..If so how much would you put in a dog weighing 30lb's and what type of sulfur would you get ..Also I have heard that you can give a dog garlic for fleas and ticks..If so , again how much, what mg. how often , what brand of garlic (would it be the same Vit. that you get over the counter for human's) and this is for a 30lb dog.. Thanks