I tore down my small frag tank last year (or the year before, time flies), took out the eggcrate and rinsed it in tap water, since the tank and eggcrate collected so much poops they stink, so I put the eggcrate in the empty tank and put both of them out door overnight. It was pretty cold, and I think the night temperature was 50 something. The next morning, I saw a mini-carpet anemone on the eggcrate, alive. It is still in my nano tank today.