fish dying

[smnw10]

I've had 2 clowns, a mandarin, and now a hermit all die since Wednesday. Nitrites are 0, PH is 8.2, temp steady at 79
Last water change was 2 weeks ago, so, I just did 5 gallon water change today (55 gallon tank)
The sea urchin lost all his decorations, i've heard this isn't a good sign.
The anenome seems to be ok, as do the shrimp and yellow tang.
One of my corals doesn't seem to be as vibrant as it normally is. Not sure what kind it is, got the tank second hand a few months ago.

My protein skimmer doesn't work anymore. It was acting up the last couple of weeks and the past week or so nothing ever makes it to the cup. I'm going to buy a new one today.

The only thing I could think of that may have some affect is about a month ago I bought 10lbs of cured live rock. The LFS said it would be fine going into an existing setup. My other thought is the clowns and mandarin were bought from the same LFS at the same time...maybe they were already sick?

At this point I'm not sure what to do or what direction to go in. My thought was doing 5 gallon water changes every day this week, but that gets pricey if it isn't going to fix the problem. New protein skimmer today for sure. There isn't anything visibly wrong with anything else.

The LFS told me with a reef tank I only need to test for PH and Nitrites as long as I did a 10% water change every couple of weeks....

Suggestions on how to proceed or did I get "damaged goods" from the LFS when I bought the fish?

 

[DJLiquid]

I learned the hard way myself. You have to place your fish in a quarantine tank for a few weeks before they are placed in the main tank. Sounds like a lot of work but that's the best way to ensure the health of your fish. I would remove the urchin (I believe it releases toxins when it dies). How's your lighting for those anemones? Did your fish have white spots (ich) on them before they died? How much live rock do you have in total? Mandarin's are really for the expert's to keep (learned the hard way on that too). I would place your remaining fish in quarantine.

 

[smnw10]

Not sure that they had ick if it looks the same as it does on freshwater fish? They had just a slight touch of white on the tips of their dorsal fin...but didn't spread from the best that I could tell so I figured it wasn't anything to be concerned about.

The lights are compact flourescent, 65 watt bulbs...4 daytime and 4 moonlight

Total live rock is somewhere around 40 lbs. Had what looked like 30 when I got it, then i added 10 and was planning on adding another 20 at the end of the month.

The urchin, not sure what his deal is. He came out of hiding today and now has crushed coral on top and has been carrying it around all day. Not sure if this is his new decoration or if it simply got stuck?