Exactly I say that all the time, the way things happen in Nature is practically perfect, these things been growing outdoors all over the place in different conditions for forever, nature gonna be here long after we’re gone, it’s us as humans just always making things kinda difficult lol 
Possibly, all of the other plants look great though, it’s just the 1 out of 6 that I’m having the issue with
I’m very lucky. The combo of my water medium and nutes gets me to the pH I wanna be at.
I will sometimes, rarely, add calmag, if I feel like it 