Bubble without skeleton

[TBAquascapes]

A customer brought me three pieces that were left after his very larg bubble coral had ejected from it's skeleton. It had been in a 10 gallon q tank until his father in law rescued it from the rocks he had put around it to keep it from drifting. It was promptly sucked into the filter.
The three pieces that came from that are now growing quite well in my coral tank, but they haven't attached to anything, or started to regrow new skeletons.
Any ideas on getting them to attach to some rock or to get them to start regrowing a skeleton?

 

[donald altman]

They will grow their on in time.. I would put them in a rubble tank of moderate indirect flow and good lighting...

 

[TBAquascapes]

Thanks for the reply Donald.
I've had them in a clear plastic container with eggcratre over the top.
One of them has attached to a piece of shell and is in the main tank now. No luck on the others attaching yet.
Any idea how long it should take before they start to regrow their skeletons?