Hello! I got my first philodendron - a Ring of Fire - about 2 months ago. It seems to be doing OK overall, but I think I am watering it wrong. 

I got it at a plant expo, and it's in its original potting mix, which seems to be a coco/perlite mix. I've been watering when the pot is light and the mix feels mostly dry (very dry on top, a bit damp on bottom), which has been maybe about every 10-14 days (I don't keep track, but I don't water any plants more than once a week). I am worried about letting it dry out too much, but have been waiting a few extra days after I think I \*should\* water in case I have been watering too frequently.

However, every time I water, I seem to be losing lowest leaves to edema. They disintegrate when touched and/or yellow and drop shortly after watering. Photo from today of one such leaf, I watered it a few days ago. The plant is actively growing new leaves, otherwise seems happy, and sits directly under a 10W Sansi bulb. I haven't seen any specific signs of pests, isolated the plant for several weeks when I got it, and thoroughly cleaned it. The roots look generally okay to me, and don't smell bad, though it looks like there is maybe a bit of mildew in some areas so maybe the issue is root rot? 

**Any suggestions?** I am wondering if I should repot it in a different mix (my go to is 1/3 orchid bark, 1/3 perlite, 1/3 FFOF). I am heading out of town for about 4 weeks soon, and will likely instruct the person house sitting for me to water only once about 2 weeks in. I am a bit worried it will decline while I am gone, so maybe I should wait to repot? Thank you for any input!

Watering/care help for my Ring of Fire?