Phal with chlorosis - what's the cause?

[JanS]

I hate to add yet another post of the "My orchid is sick, please help" type, but this has me stumped and worried.

I got this phal 2 years ago from Norman's Orchids. It was always kind of light green, even when kept under reduced light, but flowered well. It is now beginning to shoot out another flower spike but note in the photo that its newest leaf is showing yellow-green streaks and the whole plant appears it has chlorosis. My first thought was that the plant has a virus, but looking up phal virus symptom photos on some excellent web sites, it does not seem virus is the cause. Microfungus? Has anyone experienced this? I treat this plant just like all my other phals, so I don't think it has to do with fertilizing, etc.

Any advice is greatly appreciated!

[WhiteRabbit]

good luck!

[billc]

Have a look here:
Diagnosing Orchid Problems

Bill

[euplusia]

Symptoms of deficiency (and recreation) develop slowly after months and years. Most often calcium supply is not done properly, and then the plant cannot use the other nutrients. Make sure that you give regularly a soluble calcium nitrate separate from a NPK fertilizer onto the roots.
I am not sure if this is the cause, but I would do so.