This thread is deadicated to carpet anemones alone, with that being said there are great threads to help you consider what anemones would be best suited for you! And or if you are new to keeping these critters! This link should help you
Anemones dieing could be a lot of things. There a lot more sensitive than you think. Tbh there are not really any small anemones that allow to be hosted. Anemones can get massive under the right conditions. Especially carpets!
Sand dwelling anemones can include carpets, long tentacles and seabae anemones.
@esimison
https://www.reef2reef.com/threads/anemones-and-why-you-should-wait.385384/
I have been a reef keeper for 13 years and have had everything from 5 gallon pico reefs to a 500 gallon mega reef. I had multiple long tentacles in the 500 but, of course, there was ample room and places to “root.” I am specifically looking for a sand dweller and hosted that would be happy in a 60 gallon cube. I will visit other threads. Sorry to rain on your “carpet” parade.