black / copper color leaves

[jjng5]

Hello,

A couple of my plants have been discoloring on their older leaves and I cannot figure out why. The worst spots actually look black (which is completely new to me) and other areas are almost a shiny copper metal looking color. The pictures are below. At first I thought that they appeared to be nute burned but they are only a couple weeks old and have never been fertilized. Plus I've never seen black before on any leaf. I use distilled water every 3 days. All my plants are about 1-3" inches away from CFL bulbs. Temps are between 78-85F and the pH is dead on 7.0.

Any thoughts?
Thank you!

[jjng5]

Anyone have any ideas? I have been removing these leaves and want to try and save them if I can. There are 3 plants that are affected.

Thanks

[SmknVTEC]

pH of 7.0 is a little high.
Does that black leaf sit in that wet soil? If so it could be causing mold on the leaf. You can cutof the bottom leaves that make contact with the soil. What kind of soil?