Coraline Algea Question

[rocket]

My tank is tank is 9 months old and in the last few months the back wall of my aquarium and rock have been looking real good and covered in coraline. But in the last few weeks Ive noticed that large patches, 6" to 10", are turning white from the usual purple. The first patch that went white a couple weeks ago is purple again but another larger patch just turned white. Whats going on, any ideas?

 

[mmkeeper]

Did it get exposed to the air during a water change?

 

[rocket]

No, it has been under water the whole time.

 

[Krish]

Any change in lighting recently?? Also, how are your calcium and alk levels...?

 

[rocket]

no light changes. My alk has been low (6.4dkh) and i am trying to raise it.

 

[Krish]

Calcium and alk need to be in balance so maybe that's the reason for the little decline. Hope you get things sorted out soon. Once those levels balance out, the coraline should pick back up