Identification, Cyano maybe 5/6/08 Hi, My wife and I have a 12 gal. cube for about 5 months everything is going very well. We have a small rock with 2 polyps on it and is producing a 3rd. On top of the rock is a red fuzz like a velvet skin with a very well defined border. At night the red color fades quite a bit. Can you tell me what this is and if it is harmful. Thank, Ray... <Hard to say without a picture, but my first guess would be Cyanobacteria. See here for more http://www.wetwebmedia.com/bluegralgae.htm .> <Chris>

Nuisance Algae or Green Coralline Algae 04/15/2008 Good day, <<Hello, Andrew with you this evening>> I have a question regarding algae. We have a 38 gallon tank with about 38 lbs of Fiji rock in it. The rock that we used for this tank was dead. It had been power washed and cleaned when we got it, it was totally white. After some rinsing and curing in a large tub with a bacteria starting culture and the rock had cycled. We transferred it to the main tank. The tank went through a very short stage (days) of an expected diatom bloom, and a tiny bit of red Cyano bacteria which resolved itself but no hair algae at all. <<Ok>> The parameters of the tank are Ammonia 0, Nitrite 0, Nitrates 10, PO4 0, Ca 420, dKH 7, Mg 1300, Temp 75, SP 1.023. At the moment it contains some soft corals and one Pterogorgia citrina, and a host of different kinds of macro algae. The clean up crew consists of some Nerites, Astreas, Trochus, and a couple peppermint shrimp. Everything went through a long quarantine process before going into the display tank. I'm currently awaiting some captive bred Hippocampus Reidi. <<Sounds great. a nice choice of inhabitant>> What I would like to know is I have a growth, of green all over the rock. It is not hair algae, and it is not Bryopsis or bubble algae. It is flat on the rock, almost embedded one could say. The snails pass right over it and do not eat it, or seem to be able to remove it. I have also tried to manually remove it to no avail. It ranges in color from a light to dark emerald green, depending upon how much light certain parts of the rock get. The rock also has tiny specs of pink which I know to be coralline algae from the color. I was wondering if this was a nuisance algae, or in fact green coralline algae. I have been told that coralline algae goes through stages, starting out green, such as I have, and then progresses to the usual purple. <<Yes, this is in fact green coralline algae. My current tank possess this variety>> The lighting on the tank is PC 65W (1) 10,000K and (1) .03 Actinic. Filtration is with a Lifereef O/F to a Proclear 150 wet/dry trickle filter with built in skimmer. It contains LR rubble instead of bio balls, and we use Phosban and Chemi-Pure for chemical filtration. Blue bonded filter pad for mechanical filtration. All tests are done with Salifert tests kits. <<Sounds all fine to me. I do hope good maintenance is kept up with on the filter pads>> So would this be a case of nuisance algae and if so what is its name and how can I rid myself of it, or is it indeed coralline algae going through growth stages as I have been told. <<It will be coralline, nothing to be concerned about>> Thank you in advance for your time and consideration. Regards Mark <<Thank you for the question Mark. A Nixon>>