# BGA : Why Low NO3?



## nasfish (Sep 26, 2005)

Hi,

I am just wondering why low level of NO3 inducing BGA. Is there any articles that I could read about this?. Trying to search about this in this forum but most people are saying BGA due to low NO3 but not the reason why low NO3?.. Or better yet, why increasing NO3 level, to put BGA under control?

Regards


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## Craig Tarvin (Jul 26, 2005)

I will attempt to convey my very basic understanding of this topic.

I think it's a common for most people (myself included) to guess that the more nutrients in the water, the more algae... it seems like the more you feed them the more they will grow right? This assumption turns out to be wrong.

Apparently, algae growth (in the case of BGA, more of a bacteria really) is triggered by environmental conditions. When certain conditions exist, algae take it as a "queue" to start growing. I think many of these conditions relate to seasonal changes, each type of algae having different conditions or environmental queues that trigger their growth. Some of these "triggers" include low NO3 (nitrate), low PO4 (phosphate), and fluctuating (low) CO2 levels. Algae and cyanobacteria basically "see an opportunity" and take advantage of it.

In our aquariums, it basically comes down to... if the plants are growing well, then the algae and cyanobacteria are not. We should not be scared of high nutrient levels, they are our friends!


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