Phal - advices about mutiple problems

[Franzwdk]

Hello,
I'm new here and I thank you for welcome me. I'm new in growing phals too. After lots of problems with bark culture, i'm trying full water culture and it seems to work very well.
When I decided to pratice such way of culture, I had to cut all roots (every roots were roted) and remove existing mold on the bottom of the phal.
Now, the phal is growing correctly with lot of new roots and new leaves. But I had some problems regarding its well growing:
-Somes leaves burn under to much sun exposure. This leaves are growing now but were very damaged. I had to cut one. Is there a way to cure them?
-I observed one damaged area on leaves of the same side that I can't explained. Perhaeps you could help me to identify this.
- One leaf is getting yellow from it's extremity and I didn't know why.

You could find some pictures of this.

Thanks for you greatfull help and I apologize for my very poor English...