I have had a carpet for about 3 to 4 months. very healthy about 12 inches in diameter. about 2 months ago he started shrinking at night. as soon as the lights go out he shrinks up and retracts under his rock. the anemones mouth remains very tight. there is no deflating only shrinking. there is only about a one degree temp drop. So here is what Im thinking..i dont under stand balancing Ph that much but I think when the lights go out it drastically changes. does any one else have any other ideas? or suggestion to keep it more stable? Or if there is any other reason for this?