micro algue id

I have whatever these are on my sandbed and they are everywhere. I already posted this on macks dinoflagellates group and was told they dont know what they are... this was taken at 250x zoom. Anybody seen or know what these or are they are toxic and possible treatment?

Hi all, It has come on a drag originally as just 2 leaf branch. I have kept it in the back of my AIO where it gets some light and it is doing really well sometimes I think too well but I have no idea of what type it is and if I should really avoid it. can you advise please?

Hi all, Can you ID this algae for me. It kind of has some roots too. Came on a side of a coral and actually likes it in my tank but unsure if it will be any harm to let it grow Thanks