Hello, having issues with my tepins. I'm dealing with a fungus (dark tipped leaves). I'm using a diluted neem oil solution weekly and it seems to be clearing up. However, primarily at the top of the plant leaves are beginning to curl up or cup, and it's concerning me. Seems to be getting progressively worse.

My soil is a mixture containing compost, pulverized granite, and potting mix. In an 18" well drained container.

I've been checking soil for moisture, and watering every 3-4 days.