I've got a fairly new tank and conditions are good as listed below (except Calcium has dropped). After talking with a few people on they said that keeping leathers and zoos shouldn't be too bad as they are pretty hardy. A friend gave me a couple of frags, one with a zoo and another with two leathers. In fact we ended up splitting the rock that they were on and made the leathers singles. I brought them home and did an acclimation. I was told that they might not open for a few days. Well, within an hour of being in the display tank all three opened up and stayed open, with the lights on, for a couple of days. Currently the zoo opens and closes during the day cycles however the leathers, for the past couple of days have not extended their polyps. Is this normal? Do they just not open up sometimes? I bought a calcium test kit and when I first put them in the calcium was at 420. It dropped to 370 and on some advice I bought the Kent Tech CP Parts A & B. After dosing to the instructions for two days it is up to 390. Is this the reason?