Rock turning green.

Over the past week I've started noticing a lot of bright green algae starting to get on rocks. I've tried to siphon it off but it's not soft or powdery. I'm hoping it's my first signs of Coraline. Take a look and see what you think, tank was started with dry white rock in January.

 

Nope not coralline.. Coralline is purple. If anything it is just preventing coralline growth. You have excess nitrate and phosphates in your water. I'm guessing you want to get rid of it, even though you didn't say so in your post. Here are a few questions you should address so we can help you to get rid of it.
What are your levels?
Are you using RO/DI water?
How often are you changing your water?
Are you using any additives?
How big is your tank and how many fish do you have?
How often and much are you feeding (and what type of food)?
What is your lighting?

 

Actually corralline can be green as well as other colors. But that doesn't look like corrailline. Is it hard/won't come off when scratched, or is it soft and easily removed?

 

I'm pretty sure coralline isn't only purple. It can be green as well. I'm not saying that is what you have, but get a toothbrush and see if you can brush it off or not. Did you seed your dry rock with any coralline scrapings, or have a small piece of live rock with it already on it? Because in order to start growing I think it has to be introduced to the system. I could be wrong though.

 

I got on small piece of Xenia that the rock was covered in Coraline. All my parameters are in check and have been doing weekly wc's and only ro/di has ever been used it won't brush or siphon out at all so far haven't had any problems with bad algae. Also have had an explosion of pods in the past week went from not seeing any to having thousands now.

 

What type of test kits are you using? In general, phosphate test kits are absolutely useless. Hanna checkers are more accurate. I used to just judge my phosphate levels by the amount of algae growing in the tank. Less algae = less phosphate.

I would start using GFO or something to remove excess phosphate. I got a hanna checker because I wanted to be able to know when to change my GFO (because its pretty expensive stuff and I didn't want to waste it).

Being that you aren't having major algae issues, you probably aren't doing much wrong. GFO (or other alternatives) will remove that little bit of excess nutrients that are promoting that algae growth.

I feel like I remember reading that green algae like that can prevent coralline growth in the same spot. Hopefully someone could provide some more insight on that...

I do know that it also works vice versa.. Coralline will prevent other algae from growing in that spot. Maybe you should buy a rock with some nice coralline and scrape it off into the tank. Make sure your Ca, Alk, and Mag levels are in check. to promote growth of coralline. Best of luck.

 

Coralline can be purple, yellow orange, pink...all different colors and lets not forget...GREEN.

I have green Coraline growing on my Fiji rock.