White powder mildew, best remedy?

[1969gtx]

I'm starting to see white mildew. Small amounts on a few leaves, but more on the tent walls. I washed the walls with Clorox wipes, but now need to address the plants. Sm-90?
I'm sure I had a lack of ventilation, as part of the problem. The room is 12x12, which is heated. The tent is 4x4, 7'6" tall. I was running a humidifier in the tent, holding about 45%. Now, without it, I'm only at 30%.
How do I control this mildew, but maintain humidity?

 

[Bigworm1982]

I beat it with neem oil in veg, as far as flower, i took the affected plants outside and burned them

 

[CannaCola]

Do you have potassium silicate?

Keep humidty the same. Increase air movement (more circulation, doesn't need to be more exhaust. Just movement) and spray with a dilute potassium silicate.

If you don't have anything to spray with, head down to the store and get something they reccomend. Several different ways to go about killing PM... From there more air circulation will keep it away