Is this blue green algae? It pretty much covers my sand substrate. Not on anything else just there. Any ideas how to get rid of it? I tried vacuuming it but ended up sucking up the sand as well!
It is blue green algae, or cyanobacteria. I have been having an issue with it myself, and my tank is essentially spotless with nitrates less than 5ppm. I don't have and answer yet. Working on light, nutrients, and temperature to control.
Looks like it. Kill the lights for 2-3 days, then try cutting back on your lighting period. That has always worked for me. With consistent water changes and checking tank parameters of course.