Rocks Turning Purple

Jey Christopher

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when i begin, my rocks were like white. As days progressed, i had cyano problem. it was all over. Sand bed, Rocks, glasses. After continuous water change, siphoning, cleaning and altered feeding cycle and lighting period, i had them under control. after quite some time my rocks begin to turn purple and i wonder if it is that same old problem or something else. now they are not in glasses and sand. just rocks. pic attached
IMG_20190829_112049.jpg
 

Paul Sands

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Hard to tell if it’s coralline or cyano. Have you tried blowing it off the rocks?
 

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If the purple is a hard crust that you need something sharp (like a tweezer or screwdriver) to scrape it off, then it's probably coralline algae and completely normal. About 7 months after I started my tank, all my rocks started getting purple spots, and now they are 100% covered in coralline:

7 months:
Screen Shot 2019-05-22 at 10.57.45 AM.png

9 months:
Screen Shot 2019-05-22 at 11.00.16 AM.png

13 months:
Screen Shot 2019-05-22 at 11.06.29 AM.png
 
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Jey Christopher

Jey Christopher

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If the purple is a hard crust that you need something sharp (like a tweezer or screwdriver) to scrape it off, then it's probably coralline algae and completely normal. About 7 months after I started my tank, all my rocks started getting purple spots, and now they are 100% covered in coralline:

7 months:
Screen Shot 2019-05-22 at 10.57.45 AM.png

9 months:
Screen Shot 2019-05-22 at 11.00.16 AM.png

13 months:
Screen Shot 2019-05-22 at 11.06.29 AM.png
Is this something that i need to be concerned about?
 

SuncrestReef

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Is this something that i need to be concerned about?

Coralline algae is normal and a sign of a healthy, mature tank. One big benefit of coralline algae on rocks is that it will inhibit the growth of nuisance algae (like hair algae) on the rocks. The only drawback is that coralline will also form on your tank glass and powerheads, requiring periodic cleaning. You can scrape it off the glass easily with a magnetic scraper or razor blade. To remove it from powerheads, you'll need to soak them in vinegar.
 

ScottR

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just over 3 M

Just over 3 Months !!
Coralline is great to have but it has to be introduced into your tank somehow. Were your rocks started out as dry rock? Meaning they weren’t kept in water when you bought them? Anything else added to the tank?

As others stated, if it blows off easily, it’s most likely Cyano. I don’t think you can get that much coralline in a 3 month cycle.
 
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Jey Christopher

Jey Christopher

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Coralline is great to have but it has to be introduced into your tank somehow. Were your rocks started out as dry rock? Meaning they weren’t kept in water when you bought them? Anything else added to the tank?

As others stated, if it blows off easily, it’s most likely Cyano. I don’t think you can get that much coralline in a 3 month cycle.
3 rocks started as dry !! I have got one small piece which i believe is a live rock, from a fellow aquarist. It was kinda purple in color.
 

that one time

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I just started to notice purple spots like that on my rock and some pink ones too. I’m 9months in now and I was thinking about getting some kind of coralline algae to dose the tank with but wonder if I should even bother now. I imagine it wouldn’t hurt tho.
 

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