Small Powdery Mildew Spots On Leaves 2.5 Weeks Flower

Guys. This is my first grow. I have 6 plants under 296 W CFL using ebb & flow hydro. As soon as I turned the lights on to 12/12 I've been getting some powdery mildew. It's not a huge problem as there really are only a few spots on all the leaves but still I am worried it will spread and become a larger problem later down the road.

My temps drop to around 60 at night. There is no way I can increase this as I am growing in my shed with a heater and that's just the warmest its getting this time a year.

I already sprayed the plants once using Safegrow Mildew Cure
http://goodtogrowri.com/uploads/merch/SG0237PT.jpg

Which seemed to work but 3 days later small amounts came back which I think is due to inadequate cover when I sprayed the first time. ( I wasn't too liberal with the spray)

Anyways my friend gave me a small amount of a systemic mildew fungicide called Exel LG. He said to put 1/8 tsp of the stuff in to my hydro ebb & flow reservoir.
http://www.greenfireshop.com/cart/published/publicdata/MYSHOPDATABASE/attachments/SC/products_pictures/P20701.JPG

I have 2 fans that blow over the plants which I turn off at night. I think that may be the problem, I am going to switch them on 24/7 tonight to get better air flow at night when the problem worsens.

Daytime humidity is at 50%

Should I use the exel lg stuff? Do I just add it to the reservoir and let it stay or should I run it for a period of time and then drain the reservoir?

I plan to spray the plants again with safegrow in 4 days which is what the instructions said.

I am also thinking about building a sulfur burner but that seems like a hassle.

i had a powdery mildew problem couple years back n i tried everything. serenade is garbage and so are the other sprays in grow stores other than a burner . but what did actually work was eagle 20.. had to order it online...

Hi blackonblack i had same problem a few years back i tryed loads of diffrent chemicals to get rid of it but only thing that worked was a sulpha hot box ive not had problems since would def recommend. Its also good for getting rid of insects, mites thripes and white fly and also helps with keeping humidity around the 60-80%.
Just beaware its not recommended to use after 3rd week of flower all else u could get a thin covering of sulpha flakes on ya buds and mold cus of high humidity anyway here is the link to the hotbox hope info helps http://www.hotboxworld.com/about/

rizzla2008

I would not use a systemic anything on mj. Remember, it's absorbed INTO the plant and never goes away.

Hassle or no, better think more about that DIY sulfur burner.

Wet

you could try the milk cure, 1 part whole milk to 10 parts water... worked for me, you can spray it on right up to harvest. have used neem with marginal success but the milk mix seems less harsh...

neem oil works for me i tried milk but the mildew came back several times