following, as i seem to have the same or very similar in my tank. do you have a picture with the day/white lights on?
in my limited research, i saw someone say its "green" red slime, and they got rid of it using chemiclean or red slime remover. i have not tried chemiclean/red slime remover yet...first going to do a water change and siphon it out and clean the sand it's been growing on to see if that works.