Could this be from over-watering?

Light - 150w hps and/or 400w hps.
Temps - 70 night, 75-80 during light hours.
Soil - Sunshine Mix #4
Started with small amount of botanicare power plant nutes after 2 weeks of growth, and since then the problem has started and escalated.
Have flushed a couple times and problem still getting worse. Have tried increasing air flow, Have tried adding a little amount of pro-silicate..
Have tried adding Cal-mag... Still getting worse..

Have honestly looked all over the internet, I have not just come to RIU to find my answers, I have looked everywhere, asked people at a couple different hydro stores.
Still have not pin pointed what exactly needs to happen in order for the problem to fix.

Please, if anyone can really give me a solid answer or a solid conversation about what can be done I would be very grateful, thanks.

whats you ventilation like?

4inch fan sucking in air from my basement.
6inch fan sucking through carbon filter and cool tube and out the window.

i had the same problem i upgraded my venilation and started using r/o 7.0 ph water and it has not been back are you useing tap water or not ph testing your water

I am always testing ph, usually around 6.5, maybe i could raise it a bit. I use distilled water ever single time..

Also it is not happening to all the plants, 2 out of 4 plants are doing this..