1. lophophora williamsii or lophophora diffusa?
2. Approx. how old are they?

Problems (some are inexplicably resolved)
2. getting soft (some require more water, some less, to solve this problem)
3. growing holes (see photo). For the particular plant in the black container, the problem resolved itself as it's healed after I added water. Not for other ones though.
4. getting cracks (you can see them in one of the photos)

Other info: No flowers yet. RH is around 30 to 40 and T is around 26 to 28 Celsius. To my knowledge, they are not from the wild. They are watered every five days and two weeks ago were moved indoors beneath an LED grow lamp for easier climate control and a 12/12 light cycle so that they might flower easier.

I guess everyone's stumped! It sure is cute!

I meant to answer this. I think there are only 2 questions in your query: how old and which one?

Even the experts argue about the differences so I sure wouldn't know. The flowers of L. diffusa are yellowish and the flowers of L. williamsii are pinkish.

They are mature at about golfball size; it can take 10 to 30 years to first bloom.

Watering once a week seems too often to me but if you are keeping them alive and healthy with that much water, it must be right.

Thanks you all! I read somewhere that lophophoras need smaller pots due to the fact that they are somewhat rot-prone. I'm not sure what the logic is behind that. Can someone elaborate?

I put some of them in a very big pot months ago. It seems those are quite a bit softer.

I'm still curious about watering. I got gritty media and clay pots. After watering, the pot and soil seem to dry up in 2 to 4 days. Perhaps that accounts for how frequently my cacti can (or must?) be watered. Can drainage ever be too good for cacti and succulents?

purpleinopp --
Yes. They're cute as a button. Sorry, just had to put that in there