Hi skeown...I'm sure someone with more knowledge than I have will comment but I'll throw in my .02 anyway.
Purple leaves on a Phal usually means they're receiving the maximum amount of light that they can tolerate.
Much more and they may burn...at least, that's what I've experienced with mine.
However, mine are in natural light, not artificial.

What, exactly, do you mean when you say they aren't doing well?

This is accompanied by the leaves getting stiff and growing in a kind of a curl. I hardly ever say this, but the plant is getting too much light. Raise the lights so that the distance is 25% greater than now and see how they react.

Lellie & Richardal, when I say not doing well, the bottom leaves are leaving quickly and new groth is stunted. I raised the lights 2" and shortened the time they are on by an hour already, do you feel more is needed?

Could the PH of my water/ fertilizer be playing a role?

I think not unless you are using RO water. The symptoms would be different. That is enough of a change for now. Are all the plants under the light area Phals?

I am using RO water and only Phals are under the lights. I do have some Psychopsis in a west window, they bloom fine. What symptoms would improper PH be, I have ordered a meter?

What fertilizer and in what quantity are you using with the RO water?

All watering is done with 1/2 tsp of Dyna-Gro per gallon.

Leaves and esp. new ones on my Phalaenopsis amabilis developed purplish spots/margins when I left the plant in direct (behind double-glazed glass, so there's some UV absorbance) sunlight in SouthEast windowsill this summer. I use RO water for watering, and ultra-dilute Neptune's Harvest fish fertilizer weekly with, if I remember, a pinch of Epsom salt diluted. Be careful when dissolving chemical fertilizers in RO/distilled water - pH could dramatically as the water is pure, unbuffered. Dissolved Epsom salt has neutral pH. alvin

IMO its an acclimation problem, too much light too fast. It can be accompanied by new leaves ripping. Like Richard said, back it off a little and gradually bring the light back up. I get it all the time on my rehabs and orphaned drop offs. It often goes away in time and w/ proper light

Clara

Clara, that is likely my problem, the ones i'm concerned about are mostly in that catagory. I've raised the lights more and will strive to achieve 6PH.

Thanks all, Steve

Agree with Clara, it's the light. Mine all get purple when outside. I don't worry about it.

Jane