Help Identify "Purple Coralline" ?

[chiefifd]

Hi, My reef tank has been up and running for about 5 + years. I've gone thru, no algae for the first 9 months, then took bad advice, overfed, and got long hair algae. I really didn't have an understanding of what I was doing at all, kinda happy I was keeping a few fish alive .
I was just kinda stumbling along, I thought my Phosphates were high for a while (had the wrong Hannah Phospate checker). My Nitrate levels were zero, which I thought was good (wrong there)! Anyway, I've been testing my water parameters much more diligently for the last 6 months (more time on my hands).
Attached are a few photos of maybe Coralline Algae on my rocks??? I have a few spots now on the acrylic starting. Or is this something else now growing on my rocks???
Ph of 8.1 to 8.2
Salinity of 1.025
Calcium 425ppm
Nitrates 5ppm (dosing)
Phosphates 0.150 to 0.180 (dosing)
Magnesium 1400ppm
Alkalinity 8.3

 

[ichthyogeek]

The spots on the glass are definitely coralline. The fluffy bits on the rocks...I don't think are coralline. They kind of look like black brush algae, or turf algae overgrown by cyano.

 

[chiefifd]

Ya, I can't tell either. Looks like it's overtaking the short green algae on the rocks. I've just noticed the new growth today! It's growing on a few other rocks in the tank too.

 

[chiefifd]

Anyone else???
Thanks....

 

[homer1475]

I would agree with above. The glass is 100% coralline. The stuff on the GHA is either dying and being replaced by cyano, or it's just cyano growing on top of the GHA.

 

[chiefifd]

When I had the long hair green algae dieback a lot of it became covered in a brown slime that I could brush off.
Quite a bit of the coral turned mostly a white after some scrubbing, the coral has remained pretty much the same for the last year I'd guess. Nothing else has changed on the coral until a few days ago, and the small round patches of Coralline appeared about two weeks ago. I feed pretty lightly and have only three fish in the 90-gallon tank. Is this Cyano caused by excess nutrients, maybe my light feeding aren't so light?

 

[chiefifd]

These photos are under white light, not much different from the other photos.
Is this just another stage some tanks run thru???

 

[ichthyogeek]

Yeah, that just looks like dying fluffy algae. It's probably a stage the tank is going through.

 

[Dolphins18]

Hi! Cyano can be a pita! Usually manual removal has worked for me and as the tank matures it usually cuts into the cyano growth. You’ll know it’s cyano if it’s is a slimey bubbly mess of nastiness when you remove it.
Another option for fighting it is chemiClean which many people have had great success with.

 

[chiefifd]

Thanks, I did up my lighting a bit in the last 8 weeks or so. I'm going to cut back the light a bit, and use a small brush to try and remove it....