Originally Posted by
thud
"and how long be4 the live rock begin 2 show purpleish colors "
I assume you're talking about coralline algae which there are a few different colors, pink, red, purple...
Unfortunately it wont just appear in your tank, it needs to be introduced into your tank via live rock.
If your live rock does not have any coralline on it, you might not ever have it.
Choose your live rock wisely
i have 2 rocks that were purple when i got them, will thea spread to the other rocks