Brownish yellow Rocks

[molotov]

So I've been noticing more and more lately that my rocks are turning a brown/yellow colour. I was expecting more of a purple colour. My tank is about 3-4 months old. The rock I chose to use was macro rock. I also purchased live rock off a fellow canreefer to seed the macro rock. Everything in the tank is happy and healthy. All paramaters are in check as well.

I guess my question is this. Is it normal for my rocks to turn this colour?

[asylumdown]

rocks don't just turn purple. The purple is a specific kind of algae, and you should see it growing from small little spots that gradually expand to become large colonies of purple coralline algae.

That's not to say that marco rocks don't change colour as they age in a reef tank. They should go from bright white, to potentially limey green to yellow (that's a phase of early colonizing micro-algaes), and then eventually turn a base grey colour that looks more like normal live rock as microbial process on and within the rocks stain them. However, the colours associated with live rock are 9 times out of 10 due to various kinds of coralline algaes that encrust all over them, and there's many different species. There's the purple kinds, but there's also brown, orange, reddish and pinkish kinds.

Without pics it's hard to tell what's causing the colours on your rocks, but if the rock that you go to 'seed' your marco rock didn't have any of the purple species on it, you're not going to get any purple on your marco rocks.

FWIW, I have a tank that's 50/50 marco rock and Walt Smith rock. I've noticed that the orange species of coralline algae are way faster at colonizing than the purple, and the purple species don't seem to love super bright light. But in any case, if the colour change is a result of coralline algaes, you should be able to see the discrete edges of the individual algae colonies. coralline algaes look a lot like patches of lichen that you'd see on rocks on land, only way denser.

[Northernseacorals]

You want coralline now......

I will tell you that I cannot stand coralline algae, it's a pain to keep in check :smile:

Oh how I would like to give you all mine lol :lol:

[HaZRaTTy]

So I've been noticing more and more lately that my rocks are turning a brown/yellow colour. I was expecting more of a purple colour. My tank is about 3-4 months old. The rock I chose to use was macro rock. I also purchased live rock off a fellow canreefer to seed the macro rock. Everything in the tank is happy and healthy. All paramaters are in check as well.

I guess my question is this. Is it normal for my rocks to turn this colour?

Just curious are you sure its not a Diatom bloom?

[subman]

You want coralline now......

I will tell you that I cannot stand coralline algae, it's a pain to keep in check :smile:

Oh how I would like to give you all mine lol :lol:

+1 I wanted coraline algae so bad in the beginning..... now.....I can't stand it lol

[cale262]

What are you keeping your calcium level at? Depending on your ca level and the quality of your seed rock you should see a lot more coralline IME.

In my last build I also used Marco and LR at a 50/50 ratio, I kept my ca at about 450 and after four months my tank was swamped in coralline. If you want to speed the process up, you can just take a nice piece of purple rock and scrape the coralline off with a sharp edge letting the scrapings fall into your display tank, keep you levels good and in no time at all youll be scraping it off the glass on a weekly basis.

Day one.
http://i251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/th_IMG_0042.jpg (http://s251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/?action=view&current=IMG_0042.jpg)

Seed rock mixed into Marco rock.
http://i251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/th_IMG_0113.jpg (http://s251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/?action=view&current=IMG_0113.jpg)

One month, the Marco started to speckle with coralline.
http://i251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/th_IMG_0262.jpg (http://s251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/?action=view&current=IMG_0262.jpg)

Two months, there wasn't much white rock visible.
http://i251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/th_IMG_0391.jpg (http://s251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/?action=view&current=IMG_0391.jpg)

Four months. Coralline everywhere.
http://i251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/th_IMG_0566.jpg (http://s251.photobucket.com/albums/gg293/cale262/Aquaruims/Niner-Niner/?action=view&current=IMG_0566.jpg)

[molotov]

I understand there are different types/colours of coraline algea. The rocks I bought to seed with had a nice deep purple colour and are full of coraline. I was hoping that if I was going to get coraline that it would be a different colour than the brown.

I'm starting to think now that it could be a diatom bloom although my sand is in perfect condition. I'll try to get some pics up today and let you guys be the judge of what's going on.