Hello agian... My dad has started a tank not to long ago and he has been doing a good job with matenance, he has
live sand on the bottom and a few live rocks... About a week ago it started growing some black plant like , ive had that before but i just used siphon and it was gone...also my star fish feasted on it once it came back...he has cleaned out the tank several times and it comes back the very next day..... what could this be.... I told him star fish will take care of it but i dunno if that will do the work or not it just worked for me......any ideas

??