Hey, I am new to the board, and thought I would do a little intro. I am a biologist and a reefkeeper, and my brother showed me this site. Thanks Fleshy.
I was reading a couple threads here about the nitrogen cycle and thought I would post a little nitro - breakdown synopsis so people who weren't sure about what was going on could grasp the big picture. I hope its not overkill. Enjoy.
Ammonia and Nitrites are bad juju in a SW tank. I am sure you know this, but I am not sure about how much you know about the cycle. So if I am being a redundant ass, just let me know, and I'll knock it off. I'm a watershed biologist, and have kept tanks for a while so I have a pretty solid understanding of whats going on here which I'll try to share without sounding like a professor.
Ammonia gets eaten by an aerobic (needing air to live) bacteria and the waste product is nitrites. Another group of aerobic bacterica eat nitrites and the waste product is nitrates. These bacteria can and do live on anything that isn't antibacterial, including carbon. This is why it feels slimy when it you clean it.
Here's the tricky part. There are "de-nitrifying" bacteria that eat nitrate and produce nitrogen gas. These bacteria are anaerobic (no likey air), so they have to be in an oxygen deprived environment. This is why real live rock is so important. Water slowly permeates the rock and gets treated by the bacteria living in the rock's core. More turbulent flow not only helps suspend solids for removal by your mechanical filtration, but also helps force water into the pores of the rock.
There is some debate about whether or not rock can be dried out, and come back to being the same usefulness. My contention is no. Those internal bacteria are there because the rock was once a living coral and had better flow through than it does now. While the rock can maintain those bacteria in an aquarium environment, I don't believe it ever regenerates them (at least to the original level) after a full dry out.
So now we get to a point where we say, "I have high nitrates" We need to look at the whole system. In order to have high nitrates, we need two (well maybe three) things. First we need a source of ammonia, this can be dead livestock, over feeding, bad supplements or (really) bad tap water. Second we need a lack of denitrifying bacteria or (third) no good way of binding and removing those nitrates.
If we have enough aerobic bacteria in the tank, we never even notice the bump in ammonia because it gets processed to nitrite and then nitrate so quickly. If (in a saltwater system) you are seeing ammonia, or nitrites, you have a serious issue.
So, how can we get rid of nitrates? Well, if we can't generate enough de-nitrifying bacteria to do the job for us, (live rock, deep sand beds, seachem matrix, some macroporus ceramics) then we need to either remove the excess nutrient load (feed less, have less livestock, find and remove dead livestock), or remove it via another means (chemical filtration, growing and removing macroalgae, etc)
Keep in mind that if you are coming into saltwater fish keeping from freshwater fish keeping that a lot of the parameters you have used and trusted are no longer useful or valid. For marine "fish only" or "FOWLR" tanks you should be striving for a nitrate level under 20ppm, for most reef tanks, you want it under 2 or 3 ppm, and for sps reefs, shoot for 0ppm.
Good luck and happy fish keeping, and keep cranking out water changes...
I was reading a couple threads here about the nitrogen cycle and thought I would post a little nitro - breakdown synopsis so people who weren't sure about what was going on could grasp the big picture. I hope its not overkill. Enjoy.
Ammonia and Nitrites are bad juju in a SW tank. I am sure you know this, but I am not sure about how much you know about the cycle. So if I am being a redundant ass, just let me know, and I'll knock it off. I'm a watershed biologist, and have kept tanks for a while so I have a pretty solid understanding of whats going on here which I'll try to share without sounding like a professor.
Ammonia gets eaten by an aerobic (needing air to live) bacteria and the waste product is nitrites. Another group of aerobic bacterica eat nitrites and the waste product is nitrates. These bacteria can and do live on anything that isn't antibacterial, including carbon. This is why it feels slimy when it you clean it.
Here's the tricky part. There are "de-nitrifying" bacteria that eat nitrate and produce nitrogen gas. These bacteria are anaerobic (no likey air), so they have to be in an oxygen deprived environment. This is why real live rock is so important. Water slowly permeates the rock and gets treated by the bacteria living in the rock's core. More turbulent flow not only helps suspend solids for removal by your mechanical filtration, but also helps force water into the pores of the rock.
There is some debate about whether or not rock can be dried out, and come back to being the same usefulness. My contention is no. Those internal bacteria are there because the rock was once a living coral and had better flow through than it does now. While the rock can maintain those bacteria in an aquarium environment, I don't believe it ever regenerates them (at least to the original level) after a full dry out.
So now we get to a point where we say, "I have high nitrates" We need to look at the whole system. In order to have high nitrates, we need two (well maybe three) things. First we need a source of ammonia, this can be dead livestock, over feeding, bad supplements or (really) bad tap water. Second we need a lack of denitrifying bacteria or (third) no good way of binding and removing those nitrates.
If we have enough aerobic bacteria in the tank, we never even notice the bump in ammonia because it gets processed to nitrite and then nitrate so quickly. If (in a saltwater system) you are seeing ammonia, or nitrites, you have a serious issue.
So, how can we get rid of nitrates? Well, if we can't generate enough de-nitrifying bacteria to do the job for us, (live rock, deep sand beds, seachem matrix, some macroporus ceramics) then we need to either remove the excess nutrient load (feed less, have less livestock, find and remove dead livestock), or remove it via another means (chemical filtration, growing and removing macroalgae, etc)
Keep in mind that if you are coming into saltwater fish keeping from freshwater fish keeping that a lot of the parameters you have used and trusted are no longer useful or valid. For marine "fish only" or "FOWLR" tanks you should be striving for a nitrate level under 20ppm, for most reef tanks, you want it under 2 or 3 ppm, and for sps reefs, shoot for 0ppm.
Good luck and happy fish keeping, and keep cranking out water changes...
