phaleanopsis leaves/stalks turning red, flowers wilting

[lily]

one of my phalaenopsis plants is turning red. the leaves are becoming tinged with deep red, and one of the two stalks has turned completely red and the blooms on that stalk are now wilting and falling off. the other stalk is still dark green and the blooms are still healthy looking

it is planted in a mixture of bark chips/charcoal/perlite and has been watered once a week since i got it. the mix always dries out completely before watering. there are no signs of root rot (abundant, healthy looking green roots). it has lost two bottom leaves, but has two large leaves that seem healthy other than the strange red coloring around the edges and on the bottom side of the leaf.

it has been living in a bathroom that receives a moderate amount of low light throughout the day - never any direct sunlight. i'm wondering if maybe it is not getting enough light?

any ideas as to what could be causing this? i would like to address whatever problem it has right away!

thanks in advance!

[RosieC]

Usually on Phals, a red tint indicates too much light rather than too little. I've just moved one of mine further from the window as it was going red.

But you say it is not getting direct sunlight so I'm not sure.

[Louise]

Same as Rosie : for me it's usaully in case of too much light. However I have read in a book that if the red is located specially under the leaves it can be a lack of phosphorus

[Ray]

Some phals can also turn red after being exposed to too cold temperatures.

A red coloration has also been associated with a phosphorus deficiency, but the plants need so little, it's hard to imagine that being the problem.

[lily]

hmmm... well, i have been leaving the bathroom window open at night to keep the house cool since it has been getting warmer here in california... we had a bit of a cooling come in this last week though, and a bit of rain and a lot of wind. it seems to have really just happened since then! what is the lowest recommended temp? the house usually does not get warmer than 75F during the day, but i have not been monitoring night temps because i have never had any problems with any of my other houseplants...

[Mastiff]

Phals generally prefer a minimum nighttime temperature of 65F, no lower. They are warm temperature orchids.