I think you can cut them some slack in this case - they obviously have a pet store that is giving them bad (or no) information. When I worked in the pet industry, I would inquire about everyone's tank that I sold animals to - and would pump the brakes on a sale if I could tell the tank wasn't ready. Any store that sells ANYONE bags of fish and anemones at the same time, is NOT doing that. A new aquarist doesn't know what they don't know, and if the store feeds on that with predatory business practices, that is on them, not the OP.
Jay
Agree completely; cut the guy some slack. I'd bet that more people learn this lesson the hard way than are willing to admit.
My first salt water tank was 5 gallons with a Nem and a Clown using a bubbler filter and an incandescent light.
What a huge failure!
But I was relying on the "nice guy" at the local fish store. Hindsight being what it is, I see now that it was his success (putting money in his pocket) that was his priority and not my success (A thriving tank) that mattered.
The mistake has been made. I don't see any point in shaming the guy about it. If we are going to shame anyone, shouldn't it be the LFS? I'd love the name of the local fish store so I can email them and let them know how I feel about this.
Now, on to the fix...
What I can tell from the pictures is that you have set up your tank much in the way that fresh water tanks are. But a salt water tank is much more complex.
The only thing aesthetic about a saltwater tank is the manner in which you aquascape. Everything in the tank has a function that in combination with other things, creates a self-supporting ecosystem in the tank.
For example, we use live rock as a place where our nitrifying bacteria colony can establish itself and break down ammonia resulting from fish waste. Live rock is porous and provides lots of surface area for the bacteria to colonize.
Buy an ammonia badge and place it in the tank. Also, do large water changes using RODI water. Do not use TAP water.
The addition of bottled bacteria after the water change is also a good idea as it will help to establish a nitrifying bacteria colony which will aid in breaking down ammonia.
It would be helpful if we could see a quality full tank picture of your setup. Much can be determined by observation.
Also, please tell us about the tank:
What kind of lighting do you have? What kind of filtration do you run? What are the dimensions of the tank and its capacity?
Relax; we will get you on the right track.
Dom