Fungal Infection on Leaves
 

A few weeks ago I added a lot of sphagnum moss to top of pot and began a lot of watering. The bottom leaves developed a fungal infection, which is spreading rapidly. Yellow circles are present on the leaves. They started on the underside of leaves and are now showing on top side. I believe it may be "microfungal" infection. What is the best way to treat?

Should I cut off infected leaves or can they be saved with a fungicide? Does hydrogen peroxide work? Has anyone treated with Banrot plus Aliette, then Cleary's plus Subdue, then Banrot plus again?

The yellow circles look more to me like pest damage - like scale. The purple color is just from light - maybe near the upper edge of what the plant wants (Phals are low-light plants)

Those don't look that bad. It may just be an old leaf near the end of its life. Continue normal care. As always with Phals., the warmer the better.