Can someone identify my problem?

[dbl54]

When did the tank get setup? The tank was setup approx 2 months ago
When did the tank cycle? I cycled the tank for about 3 weeks before i added one live rock and 1 nurse shark and 5 damsels. The tank was clear and perfect.
Are you using live rock for biological filtration? I have one live rock apprx 15 pounds and i have put in other rock which is dead rock. With all the rocks my water was crystal clear and everything fine.
Do you have chemical filtration? (carbon?),I have a wet/dry and I am now using carbon but my water is still murky and getting worse.
When did the first fish get added? 3 weeks after the tank the nurse shark and 5 damsels.
Give the dates for each fish addition after the above first fish was added.
after the nurse shark i got 2 lion fish and a zebra moray eel. Then i added a panther grouper which i left in the tank for about a week and then decided to take him out. Then I added 2 tangs, a blonde naso and a yellow along with a clownfish. I then added a anenome (througout this time I have had 2 sand sifters and 2 star fish along with apprx 60 hermit crabs and 40 snails. The clown fish died apprx 2 days after getting him. Everything was eating perfectly in my tank. water was also perfect. Then maybe a week later the shark died, in the days following the blonde naso, one of the lion, and now the yellow tang. After the yellow tang died I did a 30 gallon water change and added carbon to my wet/dry. The water is testing perfect and my salinity is also testing perfect, but the murkiness seems to be the same if not getting worse.
With regards to testing:
What tests do you perform? I take it to the aquarium which does a nitrtate, ammonia and whatever else. They also have no idea what could be going on.
How do you test the water? (test kits, dip sticks, or ?) I personally test the water at home with dip sticks.

In general:
Who is advising you on how to keep marine fishes? Mainly store owners and the internet. I have had a couple tanks in the past just not this size and have not encountered a problem like this before.

[leebca]

This post is part of a thread noted below. It was from here:

Unusual Problem... Need help asap !