Quote:
Originally Posted by Tangster  Cyano's have a food source in the C.C now from decaying food particles and they feed on the bacteria and lowed Oxygen area is great for them.. |
To expand on Tangster's point here. The bubbles that you see in crushed coral substrates or even DSB substrates are NOT free Nitrogen produced by the denitrification process in spite of the fact that this is what all of the hobby literature says. It is exactly what he said it is. It is Oxygen produced by cyanobacteria. This is going on around all four sides of your tank where the glass operates like fiber optics and transmits light to the cyano. You can witness this on this picture. See how the light is lighting up some of the sand but eventually falls off. Where the sand is deeper, the light penetrates less deeply. Where the sand is shallower, the light penetrates further.
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