You don't have to for those two, there is enough room for both.

Thanks. Mother plant has been sun stressed & I just don't find her attractive on her own anymore, so I think I'll just keep them together until new pups break the pot & force my hand.

As long as you don't separate a pup that's too small, they both will grow larger and nicer. Gives them more light and better air circulation. Yours with only one pup may look nicer growing next to mother plant. Many of my hahnii's I let grow this way.

I found that some of my finickier ones like to be crowed in together in a pot. So what goes for one is not always good for another. Sorry, I know, no help.

I agree with Stush. My Sans, hahnii in particular, seem to grow better as a family more than alone. Kinda like people.