Coralline or Cyano? (Confused)

[Kfig7]

I'm really confused about this growth I'm having on my live rock. I keep thinking its just coralline algae but I have never seen it grow so fast. It also is starting to get on the larger pieces of substrate I have. The rock is BRS fiji dry rock.

Never had Cyano before and I just don't really believe its that. But hey you never know. It doesn't come off the rocks easily and its not slimy whatsoever.

90 gallon tank is about 2.5 months old. Parameters are as follows:

PH - 8.4
Alk - 9.5
Calcium - 450
Ammonia - 0
Nitrite - 0
Nitrate - below 5
Phosphate - not sure didn't test

Really dont think I have excess nutrients in the tank as I cant even get my Chaeto to grow in my fuge. Is this just fast growing coralline or should I be worried?

 

[matttg]

looks to be cyano?

 

[Pickupman66]

IN my experience, Coralline is a purple and the edges are a hot pink when it is growing. I dont remember it every growing on the sand but that may be possible. it looks very smooth and almost like Candy coating in my opinion.

Cyano is a more dull purple color to a red. it will grow anywhere it can and prefers lowers flows. you can see air bubbles underneath it and it can have a stringy bit that sticks up from the mat. you can easily brush it off with a toothbrush or your fingers. Coralline cannot be easily brushed off.

your photo is too small for me to tell what it is. a larger photo would go a long way.

 

[mike_cmu04]

cyano is slimy coralline is not.

 

[dublo8]

^exactly. Corraline will encrust and cannot be removed. cyano will be more like a thin coat of jelly and a deeper purple/red color.

 

[Kfig7]

These maybe a little too bug, sorry. Just doesnt seem slimy or hairy or anything like that. Its also something I cant siphon up during water changes.

 

[The_Codfather]

Do a turkey baster test.. If it blows off it's Cyano

 

[scottsdale454ss]

probably cyano, my coralline never coated everything evenly like that.

 

[oscar.millan]

Coralline grows slow even with the best conditions, this is Cyano for sure.

 

[Kfig7]

Thanks everyone. Now I have to figure out whats causing it.

Very weird. I have plenty of flow, I don't overfeed, I do weekly water changes (RO/DI) and it definitely doesnt come off if I use a turkey baster on the rocks. Maybe a Phosphate problem? I don' use anything for phosphate other than chaeto. Maybe my chaeto isnt growing because the cyano is out competing it. Hmm!.

 

[Pickupman66]

Phosphates are the main reason from my experience. eliminate them and eliminate it.

 

[LifeAquatic]

Its both! The rocks have corraline and the sand has a little cyano.

 

[JTL]

^ x2

 

[Sk8r]

If a turkey baster blows some of it off, it's cyano. If it doesn't (and the color in the photos looks far more like coralline) it's coralline.

Check your alk/calcium/magnesium balance. If coralline is growing that fast, it will trash your mg reading, and that will lower alk and cal quickly.

Honestly, I have a mature tank with plenty of magnesium, and coralline does grow. A lot.

 

[jc-reef]

Do a turkey baster test.. If it blows off it's Cyano

+1 You probably have both, IMO. Cayno can grow over the coraline too. The baster is the best test to rule out Cayno vs Coraline.

 

[Kfig7]

Thanks everyone. I did the turkey baster test again and nothing at all came off the rocks. I then used a toothbrush to start scrubbing some off while siphoning. To be honest, the toothbrush didn't remove much of it at all. A few spots here and there but its pretty much on there similar to coralline or something else. Just not convinced its cyano unless of course theres a type of cyano that doesn't come off easily.

I added some phosban to the system just for the heck of it. Going to test my mag/cal/alk today and see if that may be the issue with coralline. Thanks again.