Re: [APD] RE: Nitrogen

[Dmitri Priimak <priimak at stanford_edu>]

Thomas Barr wrote:
> > > Not the NH4.
> > > Something caused a back up of the NH4 uptake.
> >
> > Ok. I assumed mistakenly that nitrogen would only be present in a water
> > column in the form of NH3, NO2 and NO3.
>
>
> NH3/NH4 is a pH based ratio.
> Plants and algae use NH4. The lower the pH, the more that exist as NH4.
> Plants will reduce the NH3 to NH4 at some stage. 
> It's on the krib somewhere or you can find the references on line at a
> chemistry site.
> It the context here, it does not matter much. 
> Think NH4 and plant nutrient that can at high levels(not that high,
> typically unmeasurable with most test kits), think NO3 plant nutrient that
> does not cause algae blooms. 
Does rising pH and thus lowering NH4 concentration mitigate green water 
problem? This is just theoretical curiosity.

> > > It's plenty for the algae(NH4 and only a small amount is needed) but
> > > not enough total N for the plants.
>
>
> > Does it mean that plans would consume NO3, NH3 and NH4 but the rate of
> > consumption of NO3 is higher then for NH3/4?
>
>
> The speed at which the NH4 is produced is slow and steady
> generally/hopefully. Ideally it will be used up as fast as it's produced. 
> So it's gone before you can test for it.
>
> But plants need far more N than NH4 alone can supply at high light/CO2. It
> does not hurt to have morderately high NO3 levels in a non CO2 tank or very
> low light CO2 enriched tank either, but it's not mandatory either if you
> have a good fish load and feed regularly. 
>
>
> > Does this mean that algae (green water one) prefers (consumes faster) 
> > NH4 or it takes in only NH4 and alike, not NO3? 
>
>
> NH4 induces the bloom(causes the normally inactive spores to activate),
> once established, the adult algae are very tough to get rid of.
> The adults will use NO3 as well as NH4 like "adult" plants(All plants in
> relation to algae are huge "adults").
>
> The reason for my 
>
> > question is that you want to maintain NO3 slightly above zero, so as not 
> > to starve higher plants, isn't?
>
>
> Not slightly above zero, there's not need for such close tolerances,
> 5-20ppm seems fine. 
> You are getting close to bottoming out less than 5 or so ppm.
> That will cause algae as well.
Ok. Let me practice my new understanding here. That would happen because 
it would limit higher plants grows
and consumption of NH3/4. Am I right?

[snip]

> There are other cycles going on and I'm not going to get into it because
> it'll confuse you now.
> Wait for later for that.

I am very much interested in other cycles. Where do I read about them?

[snip]

> With 5w/gal and DIY CO2?
> I never had any Green water till I added NH4. 
> More light and poor varying CO2 levels will sure help Green water. 
> Make sure the pH and KH are giving you 20-30ppm of CO2. 
> The pm time will have the least amount of CO2 so that's the main one to
> check.
> I gave you the reason why, there are many things that you could have done
> to influence the NH4 uptake and caused a back up of this to induce the
> algae.
> You can answer that better than I can. 
I see. So, I try to maintain level of nutients such as to maximise uptake
of NH3/4 by plants?

> > >>    Thus I'd like to supply additional nitrogen to a higher plants
> > >>only, which means adding something to a substrate.
> > >
> > > No, this method does not work. The algae are not limited while you are
> > > able to supply the nutrients to the plants.
> >
> > But wouldn't stimulating higher order plants help them to consume more 
> > NH3/4 and thus make it a limiting factor in algae grows?
>
>
> Stimulating them helps sure, but it does not matter where you do this is
> the point here.
I see. Adding NO3 into the water column is easier.

Thanks, a lot.
Dmitri Priimak

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