White stuff falling from live rock

I hope someone can answer this question...im wondering what is the stuff falling from my live rock? I just purchased one yesterday as it has a bunch of cool organisms on it ( green plants, spaghetti worms)...and others i imagine. The rock i purchased was cured from a local shop. He assured me it was cured and ready to go. Once i placed the rock in my tank everything seemed fine until i woke up today and noticed stuff had fallen from the rock like ashes and is continuing to do so. I also noticed one of my hermit crabs on top of the rock what seems to be feeding off of it. He was at the spot where it seemed like a white area of the rock. Could this be that there are organisms dying off the rock? If so, what should I do in order to prevent anything from affecting the tank and my perculas? This hasnt happened to my other live rock..any ideas? Thanks guys...here are some pix of the rock with the so called problem of white ash looking things on it...it is mostly on the top ..you can see the discoloration...thanks guys!

 

It is a possibility that it was not fully cured or that while in transport some die off occurred. This would result in some white pieces falling off and appearing, although it could be something else. How big is the tank? The bigger, the less likely it will affect the overall water quality if it is die off. You can try to siphon as much out and off of the rock as possible.

 

I agree. Your LFS probably wasn't 100% honest w/ you. When i started my tank I bought all uncured LR and w/in a few days i had alot of stuff on the rock turning white and crumbling off.

 

hey guys, thanks for the input...the tank has been set up for a little over 2 months. it is a 20 gallon tank...i haven't bought any kits to determine measurements, as i am assuming i should do so. But I called the place i picked it up from and he kept assuring me the rock was was correctly cured..he asked me if i had any hermit crabs and i said yes, and that one of them was a big one and i did notice him eating and knocking things off the rock. he told me it could be because of the hermit crab and that i should remove him..as i did about 30 minutes ago...I also asked the owner of the shop if it could be "die offs" and he said that since it had been cured i shouldnt have really experience any die offs..the last thing he mentioned was that the coralline would grow back..so now i removed the crab in hopes of the LR being ok. I will however go out and purchase a kit for all the necessary measurements. The only thing i have is a hydrometer. Do you guys still think it may be because my tank doesnt have the proper measurements or could it be the crab i removed?? Sorry for the dim picture, i took it with the tank light off because you couldnt really see it with it on and the pic i took with my camera phone..ill try and take a better one right now..thanks again!
p.s. - i didnt order the live rock online to be shipped, i went to the store and picked it up from them directly...

 

better pic

heres a better pick of the area. Clearly you can see the discoloration on the top..sorry for the obvious glare from the light..

 

On that specific pic that rock looks really good i wouldn't worry about it if I was you just let it run a few weeks before putting any fish in there !

 

That looks fine, I don't even think it's the crab. Prolly just air from the transport from LFS to home, it'll come back.

 

thanks guys ..