Characteristics to differentiate calcareous algae from SPS

[dilbert_uk]

Hi all,

I was wondering if there are some characteristics to tell apart easily plating calcareous algae from plating or encrusting SPS.

Going only by photos, both can look pretty much the same.

I have the impression that the surface of the plates of calcareous algae is rather smooth while the surface of the plates of SPS is more rough and uneven.

Also, I would guess that plating or encrusting SPS always have a white layer on the underside that is opaque while the plates of calcareous algae are more thin and can be transparent.

Are those assumptions right?

And does someone know a source where I could get more info about that kind of identification?

 

[Whisperer]

How about polyps? Wouldn't that tell you that thing is not an algae? :lol:

 

[dilbert_uk]

Well, some Montipora e.g. have such small polyps that they appear like a rough surface only. But such Montipora always had a solid calcareous body or substrate.

Identifying precisely the existence of polyps or not would make it easy, surely.

 

[Whisperer]

You said it, they have polyps regardless of size.

 

[dilbert_uk]

But from a distance it can be difficult to be entirely sure.

Anyway, no one can answer the above questions?

 

[returnofsid]

Even Montipora polyps are visible. "From a distance?" Are we talking in an aquarium? I guess it would be possible to take a picture of it, magnify the picture and look for signs of polyps.

Can you touch it? Montipora polyps are very evident when you touch it, as the polyps retract.

 

[dilbert_uk]

No, I don't have any SPS in my tanks.

Sometimes I see some plating objects in other tanks and I was only wondering if there are some obvious characteristics that would make it possible to tell apart an SPS from a plating coralline algae besides from not having polyps.

 

[returnofsid]

Plating, calcerous algae aren't that common. I'd say most of what you're seeing is coral.