Urgent White Growth on liverock

I just came home from work and my liverock is covered in a white hard growth, it doesn't brush off. Or the coraalline seems to be dying and turning white, I don't know which.
Can anyone help or tell me what it might be?

 

coraline does turn white when it dies

 

any idea what i should do?

 

Nothing

 

When was the last time you checked your alk,cal, and mag?

 

+

=what I would think too, given the information we have.

I'm thinking you're really low on those params or they're really out of whack.

Post those results (maybe a pic).

 

it is a new tank started with salt water and cured live rock just a week ago. Just called the LFS guy i got it from and he said it can be normal when starting up that it dyes off. But that it will come back in time. I should just keep putting the purple up in.
I haven't got the tesing kit for the alk, cal and mag yet.

 

you dont really have to add purple up... but yes, the die off sounds right for a new tank. You will get growth without the purple up and in my opinion it is a waste of money lol.

Invest your money in nice salt instead of purple up and regular water changes will make your levels stay right

 

Pics

Here is what it looks like, there are many little white spots over it all.

 

Over what period of time would the purple come back?