Leaf spots on an Onc
 

Can someone tell me if I should worry about these spots and what is causing them?
This Onc is under supplemental light.

spotting
 

Some oncidiums are very prone to leaf spotting. Avoiding overhead watering will minimize but may not eliminate them. I would not be too concerned. One of my oncidiums had leaf spots when I purchased it over a year ago. The plant has thrived and none of the new leaves have yet developed spots.

l get this on oncidiums all the time it does not appear to be a problem.

I agree, oncidiums are very susceptible leaf spotting fungus but it's not something that will harm the plant. More air movement and faster drying may or may not help. I wouldn't worry about it.

Those are cold water spots. I just refrain from wetting the leaves. I put the pot under the sink and use the hand shower to water the base of the plants until the mix is dripping wet.

Ok, thank you, now what do you make of the Cats I just got? I think they are too yellow.

Isolate those sick plants; repot and throw away the old mix. Spray with hydrogen peroxide all over the plant especially the roots. The leaves are turning yellow and shriveling; they are dying very fast. There is a bacteria that is killing your plant. I noticed that the other Cattleya in the background is having the correct shade of green leaves. Better email the vendor who sold you these sick Catts.

Here is a couple more pictures.

No, they are OK. It's good color, it means they have sufficient sunlight to bloom.

some of my cats in the greenhouse got a lot of sun and looked yellowed like that...I think its really too much sun...they also looked very very dryed out...the leaves are shriveled...repot if you haven't already in a good large chunk bark media and water when dry....maybe a bit of Epsom salts would help green up the new growth that will come on your plants...be careful not to let water sit in those drain pans under the pots...in my present light stand I use a very large gravel tray, that's about 2'x4' and I keep rather large gravel in it for extra humidity and drainage....a spray routine with physan will help with any problems that may arise....good luck!