Phal species leaf problems

[SissyP50]

Hi all,

I'm having a bit of trouble with my species phals. I have one bellina that has some discoloring on one of it's leaves and I don't know what the problem is, or how to treat it. The same leaf also had brown on the end of it, so I cut the dead end off.

My other phal, a bellina var. alba had a lot of keikis when I bought it and now all but one of the keikis have turned yellow and have died. Recently the mother plant has been yellowing as well, leaving only one keiki left. It looked so healthy a month ago... I don't know what's wrong with this one either, and I'm worried the plant will die .

Both plants were bought in November and currently they are in my mini green house, the temperature is 68F and humidity stay between 45-55%.

This is my first time owning a species phal. All help and advice is greatly appreciated and thanks in advanced.