cinnamon polyps not doing well

[ninjamini]

I have some cinnamon polyps that were doing very well for months. They went from 2 to 3 to 5 to 6. About 2 weeks ago 2 of them closed and disappeared. Now another one is starting to shrivel. They are on a small rock and all 3 reached out towards the sand. Do they dislike the sand that much or should I be looking at another issue? Any suggestions?

 

[emm0909]

Well undoubtably your first reply is going to be parameters so I might as well be the one.
What are your parameters. If youre going to ask a question on here get ready to post your parameters.