red velvety stuff on my coral and rock

Question

red stuff   I have a 55 gallon saltwater reef aquarium that was set up in February. Lately I noticed a velvety dark red on the rocks and has started growing on the coral which doesn't like it at all. What is it and how can I get rid of it and off my coral? Actually it looks pretty on the rocks but am assuming it can't be good since the coral won't open because of it.

Answer
That appears to be cyano bacteria which has several causes and several solutions. The primary cause of cyano bacteria is an abbundance of nutrients, but lack of flow, and light spectrum shifts can also contribute to its growth.

The first step in fighting it is to limit feeding as much as possible and increase nutrient export. I suggest starting at feeding once per day, twice a week to get nutrient input down. Exporting nutrients can be done via water changes, refugiums or filter medias. My personal favorite media Blue Live's Clear FX.

Lack of flow may also be a contributing factor, so you may also want to try adjusting the way your power heads and return lines are set up. Sometimes getting just a little bit more flow to the area is enough to blow the cyano off the rocks.

The last thing that may be causing problems would be a light source spectrum shift. As traditional lighting systems age, their spectrum shifts more towards the red end which is of particular use to cyano bacteria. Check to see that your lamps are not past their useful lifetime, and replace if they are.

These are just a few beginning steps, but feel free to send me another message if the problem continues.