Then get rid of them!
Powder mildew (PM) loves tents. The closed in space, low air flow, and high humidity and heat are prime for PM. Instead of tents, they were lollypopping and FIMing girlies that were at least 4 foot tall. His procedure was quite simple. He has a clone space that raises all his clones. He uses a t5 to clone with. That's in a closet. His room is set up with two 1000 watt bulbs on half of his room, Co2, and the mini split A/C. When the clones go into the flowering room, they are put in the back of the room. All plants are on buckets, or lifts of some sort. As they grow, more things that lift them are removed so as they get taller, the buckets and things are removed from under them. By doing it this way, the light is at the same height all the time and the plants are started out on top of something high to keep a canopy the same height. As the plants grow, they are lowered to keep an even canopy.
When I say the plants are four foot or more tall, I am not including the bucket height in the equation. All totaled, plant and bucket are at least 5 feet tall. In his 10 x 11 sq ft room he has about three rows of four to 5 plants in each row. These are MASSIVE plants. He is only using half his room. If he put in two more 1000 watt lights he could double his grow, but he has no interest in doing so.
While the plants are raised, he hand waters those plants until they finally get big enough to be on the ground, then his ebb flow system works right again. His plants are in trays, so that whey they are shorter, the excess water runs over the plastic raisers or buckets into the tray. It seems like a bastardization of several different methods, but I like that it allows you to harvest plants every few weeks, but not have to harvest an entire room.
By doing it this way, he keeps a good rotation of plants, the plants arent congested, and there is lots of good airflow. Good airflow, good temps = no powder mildew. At any given time, he is only 3 weeks away from a harvest of something. I liked this method for several reasons. I plan to raise more than one strain. One of my strains takes 11 weeks in flower. One strain takes 8 weeks. Because I dont want to raise just one strain and because I dont want to wait an entire grow cycle to get different strains, I decided this made the best sense for me. My main concern was smell. He is running two 6inch Can filters in the grow space. His CFM requrements are for 405 sq ft, he is running fans that are big enough to scrub the air, but he doesnt trust it, so he has two running, double what is needed. It is a closed room. No ducts. The Mini split is strong enough to keep the heat out of the room with the two 100watt bulbs.
You can stand outside of his grow room and not smell a blessed thing. Open the door... nirvana!
I'm copying every single thing he did, which is why you see a T5 in my photos on my grow journal. I didnt know I would do this until after I had bought my second tent.
I just did a smell test with Limburger cheese (no plants in the grow room at the time). Horrid stuff, but the air scrubbers worked very very well. That stuff stinks so bad that I had to put a little bit of vicks vapo rub under my nose to stop from smelling it before taking the bucket into the grow room.
Right now I have my baby seedlings which are in veg in the flowering room. Its the only thing I have in there, and I am so tickled with myself I can barely stand it. If you wanted to run two spaces, simply frame in a wall and separate the space. If it were me, I'd run my 12 hours at night, both lights when its cooler. If you need to use different feeding times for two sets of plants, then stagger feed in the same room.
This is MHO. I am currently on my first grow. I have had over 20 years raising grapes, peaches and prunes in the Sacramento Valley in Calif. I may be totally wrong... but thats where I am going.