[APD] Re: Nitrogen #2

[Thomas Barr <tcbiii at earthlink_net>]

>Does rising pH and thus lowering NH4 concentration mitigate green water problem? This is just theoretical >curiosity.

No. Once started, you have to kill what is there. NH4/N3 induces it, raising pH might have some influence I suppose, but you'd have to keep the pH very high for awhile and then it would harm the plants as well.

>> 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 plants would consume NO3, NH3 and NH4 but the rate of
>consumption of NO3 is higher then for NH3/4?

Generally, yes.
You simply cannot add enough NH4 using CO2/high light without overloading the system and killing fish and producing algae blooms. You can do this "balanced notion" at  aslower growth rate with a non CO2 method.

You can try to add more and more fish to supply the Nitrogen needs for the plants at high light/CO2, but you'll crash the system and get algae blooms due to the back up of NH4. Plants can only take in so much before there's some for algae.

This directly expalins why NO3, PO4, traces can be at high levels(add inorganic sources like KNO3, KH2PO4), but why you cannot overload the tank with fish to supply the N, since it starts off as NH4/urea waste first. 

The rate is slow enough to keep the plants happy with fish food/waste, but adding CO2 increases this and the N needs for the plant.

So we can add liberal amounts of NO3 without issue.
I've tried to amply the NH4=>NO2=> NO3 bacteria and overfilter the tank etc, but it does not work, the algae get the NH4 before the bacteria in virtually all cases.

A slight excess of NH4 might be solved by intense filtration, but so would not feeding so much/lowing a heavy fish load:-)
That is better in the intererst of the fish any so that is a better approach(and less costly/simpler and more robust in the long run) 

>Does this mean that algae (green water one) prefers (consumes faster) NH4 or it takes in only NH4 and alike, >not NO3? 

NH4 induces a bloom. Once started, the alga can use either source of N and is nearly impossible to get rid of with blackouts and nutrient management.
Spores will not bloom with NO3 only. They need a certain concentration of NH4 for certain time frame to bloom.
The problem that caused the NH4 may very well have come and gone by the time you see the GW, but you can remember what you did the last 3-4 day prior fairly easily and see if you can relate it to NH4.
Every case I've ever seen had something related to NH4.

Lower lighting makes the intensity of GW and water changes/blackouts much more effective.
2 w/gal folks seldom ever get GW.

But people want the high light so..................

>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?

No, it would limit the algae spores from being activated. Adding NO3 will add enough N at high liught/CO2 to supply the plant's growth needs.

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

APD perhaps. 
You take care of this algae problem first. 

>I see. So, I try to maintain level of nutients such as to maximise uptake
>of NH3/4 by plants?

You got it.

>But wouldn't stimulating higher order plants help them to consume more NH3/4 and thus make it a limiting factor >in algae grows? 

No, it's not limiting to the plants, they have plenty of NO3.
So the N is still being supplied to the plants but little NH4 causes the algae not to bloom and cause probelms.

Plants do not need NH4 at all. they do fine with nothing but NO3.
They are huge and have plenty of reserves to convert NO3=>NH4. Algae don't, they exist in a different niche, the microscale.

One molecule of NH4 is worth much more to a single celled spore than a 10^12 celled stem plant.

>I see. Adding NO3 into the water column is easier.

Well it does not cause algae and adds enough N for the plants. CO2/high light makes things more troublesome until you get all this right, but it's not bad thereafter.

Less light(2-3w/gal) makes any method easier and plants do great at this light level(all plants, even the so called "high" light plants). 

Faster is not better.

You can join the Aquatic gardener's association and get TAG as part of the memebership.

No one has ever put this NH4/NO3 split together in context of algae and planted tanks, so you will not find anything on it in books etc. I've done all the research myself. Same for PO4, Trace dosing, general algae issues, substrate cycling, lighting, dosing routines, testing etc.

Regards, 
Tom Barr



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