# Cyanobacteria in the gravel?



## maboleth (Aug 13, 2013)

I've noticed cyanobacteria growing deep in my gravel, right in front of the glass. Possibly because of the sunlight. However, it doesn't grow anywhere else in the tank. Does this pose any threat to the tank and should I leave it alone? I vacuum the gravel wherever I can (hard to do because of a dense vegetation) with every water change.


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## Yo-han (Oct 15, 2010)

90% of all tanks have this. Nowhere in the tank but between the gravel and the glass. It is just because lights hits it and there is too little water movement, so anaerobic circumstances can proliferate. Nothing to really worry about. I remove it from time to time during a water change. I scrape it away with an old credit card while sucking it up with a hose. I know Amano sucks away the aqua soil from the front from time to time and replaces it with new soil.


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