This is my spec x mira. I've had it for 7 months. It arrived in real bad shape - the bag it was in was ripped open and the plant was very wilted, the roots completely dry. Anyway, a month later it was fine, and started to unfurl new leaves. It's done great until about a month ago. Then I noticed an overall yellowing of the leaves. They used to be a more medium green color. Then, spots started to appear on the leaves. And now, just in the past week, a golden brown/orange something is taking over the leaves! It isn't making the leaves dried and and crispy, rather they are going soft in those areas. It isn't just from the leaves being old, as it's appearing on newer leaves as well.
It is kept in my highland grow rack; temps normally 55-77, humidity 65%-85%, 16 hours of light on a shelf with 4 40 watt floursecents. The media is 1part each: Aquatic plant soil, coco shell chunks, chopped LFS. It's an airy, chunky mix. Watered about once to sometimes twice a week.
None of my other neps are showing any of these same symptoms. I haven't ever had a disease or fungus on my neps, so I'm not able to recognize it.
It has been getting cooler at night. Although kept normally at 55 for a low, this week it hit 44 twice. I wondered if maybe that's too cool...but my thorellii x (spectabilis x northiana) isn't skipping a beat despite those low temps.
I did a meticulous pest check and found nothing. I'm familiar with mites, scale, and mealybugs from having dealt with them in the past.
Please help! It's degrading quickly and I don't want to lose it!
Whole Plant, in a 5x6 pot: The curled leaf in bad shape with a hole in it is from when it shipped and was dried out. Not a pest.
Another angle. Here you can see the coloring on a lower leaf:
View from above. Here, you can see it on 3 leaves. One on the leaf on the bottom of pic, one leaf at the top, and one on the left. The one on the left is a fairly new leaf, though not the newest. It is inflating a pitcher.
Pic of the newer leaf:
The pitcher inflating from that leaf: