Weird Spot on Catt Bulbs

[Corsetière]

I recently was given these two rescue Catts and after cleaning them up a bit I noticed that they both have dark spots on one bulb on each plant. I googled "black spot cattleya" and only got results with black spots on the leaves. Is this some sort of rot or just sun damage? Should I cut off the effected bulb or is there another treatment I should use? The rest of the plant looks fine, no other obvious damage...

[MaisyMay]

I have rescue cats with the same spots on the bulbs, dry hard and not mushy right? I think that it is a calcium deficiency. Google it, I don't remember where I found this information probable this forum I am treating it with dolomite lime and oyster shells .

[Corsetière]

Good point, MaisyMay. I was wondering if this could be the case. Yes, it is definitely not mushy. I do have dolomitic lime here, so I think I will give it a shot. Thanks for the reminder!