How do you get your live rock purple?

I found if you have a good patch going, to scrap lines through it. This spreads the coralline algae around the tank to take hold and continue growing in new places, and the lines you scrap in the existing stuff fill in very fast. This is just something I do to help propagate it.
I was using Purple Up, but have stopped and only use it very rarely, once a month, and I dose calcium weekly. But have stopped because my CA is reading 500ppm, with a AP test kit, which my LFS does not like. My Alk is 3meq/l.
 
my coraline algae has spread out... and it's make a green, purplue color.... but it's take a time.... around 2-3 month since i get my live rock....
i also add calcium everyday.... and always check my calcium every week
 
Good to hear someone else has some green coraline. I have green stuff that looks like coraline, I was going to ask if that was also a colour it could be.
 
Funny thing about coraline algae:

"Growth of coralline algae over the rock's surface will close off most of the small channels and passageways, largely contributing to the decline of the rock's biological filtration capacity. Hobbyists may further contribute to this degradation of filtering capacity by gluing coral fragments to the rock's surface, thus sealing off more of the pores. This may make the inside of the rock anoxic and, if there is much organic material inside the rock, it will start to rot. If the interior of the rock is subsequently exposed to the tank environment, such material could be deleterious."
 
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