freshwater coraline algae?
 

I while back, I briefly met a fellow who was growing what he called
"coraline algae" in his freshwater tanks.
I found it quite beautiful and would like to replicate it.

Visually, the form is similar to very thick paint. The colour range, I
would describe as "preshool" greens and yellows.

The fellow was using a home-brew CO2 bottle, some form of Iron
supplement, and
another mineral supplement -Potassium/Calcium(?).
Both of the supplements struck me as coming from a land-plant nursery.

Has anyone had any experience with this type of algae?
Thanks,
Mike