pure ocean water, but dead fish! HELP

I just started my first aquarium, and yes, I suppose I was dumb to begin with a salt water one. I bought pure ocean water to fill my tank, put in a heater for it to be 78 deg., put in artificial plants (for the time being), a bubble maker, and a few little houses. I bought one female blue damsel, and one small oc clownfish. They were together in the tank I purchased them from at PetCo. I bought them yesterday and put them in my tank, after letting them float in the bag for 10 minutes. Neither would eat yesterday, as I figured, and I came home to a dead Clownfish this afternoon and it broke my heart. I tested the water, and according to the strip, the water levels (nitrate, nitrite, Ph, hardness) were perfect. The temperature is 78. Why did this happen?
Now, a few hours after the death of my clownfish, my blue damsel is acting very weak. She is obviously scared/threatened because of her dark blue, purplish color. She has some white tint to her mid-section back to her tail fin. She literally lays on the bottom for 2 minutes, barely moving her fins and breathing rapidly, and what looks like hardly at all-- THEN all of the sudden, she basically jumps up and swims around the tank with energy, bolting everywhere for a few seconds, then she'll basically float back to the bottom and appears dead again. She isn't having any kind of reaction to me putting the net in the tank, she doesn't bother to move.. I tried to ease it toward her to see if she was alive, and she even let the net touch her, then flinched, then continued to lay there, and just had another episode of liveliness again.

*note- I put the fish in the tank with nothing else in it- nothing added to the pure ocean water at all. Last night, I added the appropriate amount of water conditioner. After coming home to the dead clownfish, I then went to the store for some things, and then added a small amount of healthy, live bacteria made for sw or fresh water tanks. This is the only thing I've added, other than a few drops of the conditioner, since I took out the clownfish. Also, I recenly turned off the bubble maker, because I read by a few on here that it's not good for them in a saltwater tank. However, I have read a lot of places the exact opposite so I can't decide what to do.. on or off?

I went to 5 stores, and no one hardly answered my questions or gave me any advice at all. I researched and thought the tank was okay, but apparently it's not.
Please help! I really, really do not want to kill any more fish, and if there's hope for my damsel I want to know what to do to save her.

Thanks in advance

Thanks for replying to my questions! I bought the 'Real Ocean Water' from PetCo, and they said I would be "good to go" with it. I have artificial rocks, some fake seaweed, two houses, and a 'wrecked ship', and a bubbler. Plenty of room for them, yet also plenty of places to swim in and out of/hide in. From what people at stores told me, my fish were going to be fine in the ocean water.

That's what I thought.. but I went to a small place too, and the man was telling me to buy the ocean water since I didn't have my tank set up yet. They actually tried to sell me things a lot more than PetCo or PetsMart did! I was surprised by that, but that's mostly just because the PetCo people were very side-tracked because it was dog day haha. I do like that they provide care sheets on their website that provides new fish owners with general knowledge and upkeep info for each fish.
Well good luck to you on the creation of your tank. I will continue to research before getting more fish.

Thanks Andy, your comment was very helpful. I am letting my tank continue to run, and I will remove the air stone.

My tank is a 10 gallon tank. My boyfriend had it at his house and just gave it to me because I have been wanting to have a fish tank. I bought a new filter from Walmart, it is a large AquaTech filter, made for tanks at least 10 gallons.

I am almost afraid to get any more fish because I would hate to have it die. I didn't think it would be so difficult- we had a very large tank when I was young and it was filled with saltwater fish and aquatic life. Therefore, my father has experience and I figured I could get him to help me out if I needed him to. I feel though, that I may need to start out with freshwater, easy-to-care-for fish and work my way up.. but I am not sure. I am definitely willing to put in the needed work and time to care for sw fish, I am just afraid I don't know enough and will kill more and throw away money. I have already spent over $80 on setting up the tank, and that's not counting the price of the fish and the ocean water my boyfriend purchased for me.