Can Anybody Identify These?

Hi,

I have a form of algae growing which I quite like but not sure if it is okay to leave it. I have also noticed a disc like shape growing on the rock as well.

I have tried to take a couple of photos and would welcome any advice on what they are and if I should remove them?

Difficult to see but maybe Caulerpella

take a look at

http/saltaquarium.about.com/od/algaephot...oto_Gallery.htm

Is the shell shape in your second photo soft or hard?

Seffie x

its soft