coincidence?

[wolvesheart]

The other day I added some cured Live Rock to my tank. It is doing well and all my tank readings are normal.
amonia 0
nitrite 0
nitrates 0
ph/alk 8.2-8.4 / low/normal
salinity 1.025
The other day my outwardly healthy arrow crab died and last night my featherduster is out of his tube and not looking healthy.
I am not a big believer in coincidence but can find no obvious signs of stress or imbalance. My anenome is ecstatic that the Arrow is gone. It is back out in the open and spread out wide. My hermits are enjoying an all they can eat crab leg buffet, and I have a burst of coraline growth. (what did the LR add that caused the Coraline to explode? It did that when I added the first rock but then calmed down. Should I be adding some suppliment?)
Any ideas?

 

[dad]

how much rock did you add? did you take out any water to account for displacement? how big is your tank?

 

[wolvesheart]

I put in a really pourous 10lb piece. I did not remove any water and I checked the salinity it checked out a little high. 1.025 but still within parameters I believe. Think I should take out some salt water and add more fresh water?

 

[dad]

yes, try for 1.023.
as far as the coraline goes; some people have all the luck,lol
keep a close eye on nitrate levels for a day or so. a 10lb rock may have something in it that has deceased? good luck!