Why Do We Dose N03?

[aberg12012]

Just a quick question...

Is there any reason to be dosing KN03 or any of the other methods of adding N03, when N03 is already present in our aquariums as a result of the bacterial process of breaking down fish waste? My tank has about 20-30 ppm N03, and yet every thread on this topic says I should be adding KN03? Instead of even bothering with KN03, why not just feed the fish more to create more N03? Is there something I'm missing here? Is the N03 produced via the breakdown of fish and food waste not the same as provided from KN03 or any of the other fertaliztionl methods for N03? Unless you do ALOT of water changes, N03 is practically unavoidable in a FW aquarium, and IMO 20-30 ppm is nothing compared to what I've allowed other FW tanks to climb to. But then again, this is my first heavily planted tank...

So the next question is... Do the plants consume nitrates faster than can be provided by the biological process? If so, this would explain things... and then I would expect after a while to see my nitrate levels in my newly planted tank go down?

Thanks :)

[phanmc]

In some cases, like a heavily planted high light tank, the NO3 gets consumed faster than the fishes can generate. The problem with overfeeding fishes to generate more NO3 is that overfeeding will lead to other health problems for the fishes.

You'll notice a drop in your nitrate readings once your plants begin to grow. If you still detect nitrates after the plants are growing then you won't need to add more NO3, but if you see no nitrates then you'll have to add more.

[aberg12012]

Ok, that is pretty much what I was assuming... so for now I don't need to worry about nitrates untill they drop. I began injecting C02 yesterday and WOW! Not only did the plants start bubbling like crazy, they were noticably greener with in 6 hours. (Although that could have been all in my head :D )

[anonapersona]

Even though your nitrates are at 30 ppm yesterday, they may start falling fast if the plants have enough light to bubble from photosynthesis. As the plants use up nitrogen, they also use up other nutrients and you may be phosphate limited or run short of iron or some other nutrient.

[aberg12012]

Well... I went on a shopping spree the other day which included such things as No-salt, Epsom salt... and yes even Fleet Enema (the most embarasing thing I've ever purchased. lol) So I got the macro's covered, but just seemed a bit off to be dumping nitrates into my tank when there already is ample amounts. :D But I understand now that they may quickly drop due to consumption, and that I will have to be supplementing. It's weird... all this time in the hobby I've been battling nitrates in my FW tanks... now I'm thinking about having to add them? lol

[Captain Hook]

Alot depends on the amount of light you have. If you have a good amount, and the plants are growing fast, obviously there will be a greater demand for a source of N.

Sounds like you're well stocked on fertilizers now which is good. Try to get into a fairly consistent routine of water changes, fertilizers, and a good level of CO2.