ok well I have a 75gal reef and see a lot of air pockets in my live sand the bed is 3-4 in deep and the bubbles are against the glass with purple looking algae in the sand around the bubbles any idea if its bad
I have been told that the air bubbles mean your sandbed is working because they are the nitrogen gas that results from the denitrafication process and they are on thier way to escaping through the water column into the atmosphere. I am not the expert but this is what I've read here on reef central. Also the purple algae next to the glass below the sand line is most likely only on the outer edge of the bed where it recieves ambient light from the room.
well it's bot 10 months old now and am getting coraline in the tank now and don't get algae blooms at all all my levels are great now I have 1200 gph flow in the tank with no dead spots and a 30gal sump