I have described in a few previous posts how I managed to fix my scheff problems.
First I replaced them....
Then I used a functional garden pot that I put inside a more decorative pot and tjhere is a good bit of air space between them.
I made a potting mis of 1 part sand, 2 parts organic soil and 1/4 activate charcoal (it keeps the soll fresh and improves drainage. After repotting with this mix I drilled a crap tone of holes in the utility pot, bottom and sides. I think drilled lots of holes on the bottom of the decorator pot and some on the back side of it. Those I did big like the size of a quarter. The pot is made of this glazed expanded foam stuff. Looks like ceramic but is very light. I did that to improve airflow.
I have had very few problems since I did that in in November. I actually have to trim back a lot of leaves at the top of my plants.
I also added 2 6500k LED lights and will be adding some T5 grow lights next month (I don't want to move another 48" fixture)
So bottom line is I think they get much water and not enough light.