man, first understand that most grower go thru a stage like this and that it never warrants slitting your wrists! I fought with powdery mildew once, not fun. but be happy its not spider mites! The dehumidifier is a good suggestion but I might also suggest a sulfur burner! I found that neem only slows the powdery down, but after three days with a light sulfur cover it will disappear. use caution with the burner. Filling your whole house with sulfur is not good for you and will give you one hell of a head ache. good luck bother, good things will come!