Hi John,
It's great that you are willing to ask advice and learn
Welcome to a wonderful hobby and the most information you will find in any one place about it!!!!
Now let's save your anemone.
Can you return it to the store? It's bleached to begin with, and, honestly, without some form of intervention, it likely will perish. If you can't return it to the store, please try to find a local reefer/reef club, and someone will try to save it for you.
Your tank is very likely (there are few absolutes in this hobby) way too immature to house this animal, and, as was pointed out, the substrate is not the way to go for a successful reef. I don't want to assume too much, but, since this is a time delay way of communication, I will assume you are fairly new to the hobby.
Step 1. Get the LTA to a more suitable tank. If your store won't take it back, and you don't know any local reefers, you can find locals to you by going to the Reef Club forums on this site, scroll down, below the sponsors, and you will find it. Best to you there.
Step 2. How big is your tank, and what other living animals do you have in it? Do you know that fish, corals and anemones are all living animals? I know that sounds dumb, but.... Most people that visit my house think they are plants
At 8 weeks, your tank may be cycled, have you tested your ammonia and nitrite?
Step 3. Do you have a test kit? If no, this should exist before living creatures. Please test, at a minimum, your nitrite and ammonia. This is how you will know if your cycle is over. I would recommend sharing that information here, and perhaps you will garner more information if it isn't.
Step 4. If your cycle isn't over, my recommendation would be to remove all your animals. Then, remove the substrate immediately and decide if you want bare bottom or a sand bed. An LTA is a sand dwelling creature, and, therefore, if you want to have it (back or another one) you will need a sand bed. If the cycle isn't over, I'd just siphon out the water, scoop out the gravel, and dump in rinsed sand. And roll on with the cycle. If the cycle IS over, then I'd pretty much do the same thing, and, depending on what you do with your animals, test, test, test, monitor, monitor, monitor, and water change, water change, water change. If you don't have live rock, you are likely starting over at this point. You've started out behind the 8 ball my friend, starting over isn't a bad thing
I wish you the best, and there are lots of paths to take from where you are, but, these four steps are the basics and you should seriously consider following them.
.
