Phaius - Black spotting/leaves turning black

[Kokothefirst]

Tips of my phaius turned black early on. Stopped fertilizing, and this stopped. at the same time, small black spots appeared towards the base of the leaves, but did not seem to spread, so I attributed to fertilizing also. Now I have a different appearing black spotting happening, and one of the smaller leaves is rotted almost entirely. Help! Any idea? Obviously a fungicide could be in order, but not certain which one, as not many have these plants, and I cant find like symptoms anywhere.

Thanks!