On some of my new Thanksgiving Cactus growth, small black patches are beginning to form. Too much sun? Too much water?

Question

Hello,
My mom has had this Thanksgiving Cactus for almost 2 years. It has done nothing for her. I took over maintaining it in the spring of this year and it has doubled in size since. Most recently though I noticed that it was not using the water that I gave to it (pot was still heavy a week after I had watered it), so I figured I would give it more sun to cause it to drink up the water. That is when I started noticing these black spots on the tips and sides of new growth. It is not on the older segments.
I was using regular potting soil. Did some research and found out many wrongs that I was doing; Mainly – the soil is wrong, I have been watering it too much, and I have had it in the direct sun light too much. So, I went out today and got some potting soil for cactus plants and repotted it. The roots do look ok, and no bad smell. The root system though is only half the size of the plant – about the size of a base ball.
I removed a couple of the new growth that has these black spots on them (4 of them). Should I leave the rest (about 5 more). What do you think it is from?
Thank you for your assistance, I truly appreciate it. .

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Answer 1

I would remove the rest of the leaves with the black spots. It could be a fungal infection from overwatering, or it could be from too much sun. It sounds like you have the issues under control, less water, less sun, and courser soil.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/fungal-lesions-on-cactus.htm