View Full Version : Biology of good vs. Bad bacteria?

05/09/2012, 06:22 AM
I have a small amount of cyano that seems to annoy me enough to get thinking pretty hard. Its just my OCD....

But, I'm wondering what nutrients are required for "good" bacteria to grow as opposed to "bad" bacteria?

For instance, reducing phosphate levels will inhibit cyano growth, yet I don't belive that phosphate is needed to grow nitrifying bacteria. Also, correct me if I'm wrong, but both cyano and nitrifying bacteria need organic carbon, Right?

I guess what I'm asking is how do we maximize the good bacterial populations as opposed to the bad? Surely there are many, many different species of good bacteria with all sorts of different requirements and just as many bad ones with similar needs.

Randy Holmes-Farley
05/09/2012, 06:47 AM
Cyanobacteria doesn't have fundamentally different needs than other bacteria except it can photosynthesize, and it can possibly get nitrogen from the air (whether it does in an aquarium with other nitrogen sources, however, isn't clear). All bacteria need sources of phosphorous, such as phosphate. Nearly all nonphotosynthetic organisms need organics, but some nitrifying bacteria may not.

In general, reducing organics and phosphate is a good way to deal with cyano problems. I've never heard of anyone having a problem with ammonia by driving phosphate or organics too low so that the nitrogen cycle doesn't function. So I would not worry about that.