Sulfur burners, would it harm a plant in flower?

So ihave a slight powdery mildew problem and I picked up a sulfur burner, my plants are in eight weeks flower, would it harm them if I used it?

Also how do I use it? I have it suspended up above the plants, how full should I fill the little cup? How long should I run it for? Run it at night correct?

I have a friend who ran a sulfur burner and he said he filled the cup up all the way and ran it for 12 hrs and it took the smell out of his buds, whenhe dried the budsthey had no smell and he said it was because o the sulfur burner, is that possble? Could a sulfur burner turn my nice nugs into schwaggy garbage?

anyone got any input? im kind of nervous to run it

First, fill the burner cup up halfway with sulfer. When the lights go off burn it for three hours, and then shut it off. Do that for three consecutive days (emptying and refilling the cup each day).

That is how you do it, as for it being ok to run in the 8th week I dont know for sure.