What happened here?

[CSJIII]

So I started a 14 gallon biocube back in late November 2013. I wanted as much filtration as possible so I have my center chamber filled with cheato for nutrient export and decided that I wanted to use a skimmer. The skimmer had been working very well until the other day when I noticed that the skim mate wasn't as thick and dark as it used to be.


The coralife skimmer that fits in the rear of the bio cube 14 uses a lime wood airstone, which brand new, looks like this..

Upon inspection, my airstone looks like this..

What the heck happened? My tank is looking good and progressing but wondering what the heck the black growth is.

 

[Mike J.]

Algae loves to grow on areas with high flow and aeration. An air stone is the perfect place. Replace it or you can soak it in vinegar.

 

[jasonp87]

They get that way over time. As long as the skimmer is functioning correctly you don't need to do anything unless it bugs you. Once it starts to block air flow and reduce the effectiveness of the skimmer I recommend replacing it, they're pretty cheap.

 

[CSJIII]

When I bought the Coralife skimmer, I purchased replacement stones. I did change it. But its just so black and was worried it wasnt algae, that it was a bacteria of some sort. Should be back to fresh now. It has really been working well in my small system.

 

[TarHeelReefer22]

Are you using the compacts or did you upgrade your lighting?

 

[mothership.mantis]

Looks perfectly healthy to me, my bio cube has been set up and doing great for 7 yrs now, just got to keep intakes on back wall free of mushroom growth, a new air stone now and then, it is just algae