PM can be a relatively simple fix- first off, what is the relative humidity in your room and what kind of fluctuation do you have in RH between lights on and off? Same with temps, what ya got? To eliminate pm for good, you need plants to be healthy enough to fight it off themselves...which means an RH shift of less than 10% between lights on an off. I generally prefer to keep things in 50% range, though this often requires dehuey and humidifier. Temps i was always told need to stay within 7-10 degrees between on/off cycle.
IF you can maintain these temps/RH levels, something as simple as milk/water will do the job. Ive demonstrated this in several friends spots who got PM due to inconsistent environments. I had pm for about 6 months several years back and until i got room dialed i just couldnt shake it. Once room is consistently there, any of teh pm applications things will work because once sprayed and surface mold is gone plant has a MUCH greater chance at fighting off spores/spreading.