I bought first clam last week. I got him online. He is a Maxima clam about 1.5 inches. I drip acclimated him. My calcium level was 500 when I tested a couple days before introducing him, ALk is 9 but I don't know what magnesium is as I have never tested for it. My tank is 55gl with 4 54W T5s, 2 actenic and 2 daylight. He is sitting about four inches from the bottom on LR. I have been target feeding with Phytofeast from a syringe everyday. I really like him and hope he has a good home. I have been reading some of the threads on here and I don't notice anything unhealthy looking about him according to all that. He opens all the way during the day, incurrent and outcurrent siphons look fine, mantal is not frayed or worped. He has some flow where he is but not a lot. He has been reacting quickly to my hands getting near him and to shadows but after reading some on here I got curious so I stuck my hand in and he didn't close up when I touched him. It is 4 am and the light has been off since 8pm so he was already partially closed and he did react to my hand but didn't close up all the way. Is that a bad sign? anything you can tell me would be great. I have some pics of him to show you.