Re: [APD] NH4+ dosing

[Thomas Barr <tcbiii at yahoo_com>]

> My impression was 
>that the amount of N added by NH4 was fairly low compared to
>the EI 
>method but the plants used are more likely to do well in low
>nutrient 
>environments.  The lighting is fairly low aswell.  It looks to
>me like 
>the plant mass is actually fairly low and that the bulk of the
>layout is 
>taken up by rocks so the amount of nutrients need is less that
>if the 
>tank were that filled with stem plants.  Also note that they
>dose small 
>amounts, 2x a day.

>Dennis

Yep.
When you add more light You will get algae at higher levels.
With lower light, non cO2, most of the N can come from NH4(fish
waste).

I find it hypocritical of some that suggest dosing NO3 is
somehow bad for plants or fish at moderate levels, and that
dosing NH4 is fine for fish. It is highly toxic even at low
ranges.

A precise measure of how much NH4 induces an algae bloom in an
otherwise healthy tank is dependent on a number of factors. 

Lighting
Fish loading
Bacteria/O2 levels
CO2
Plant biomass(see CO2 and how it can regulate NH4 uptake/growth)
Status of the plants' health at the time.

More light: bad
More fish: even worse
Bacteria and O2, will remove it and convert it into NO3 and use
up a lot of O2 in the process.
CO2, drives uptake of N, so if you louse that up, you have
issues right away
Plant biomass varies tank to tank greatly, species to species
differences also.
Status of the plants: they might be hurting for other things
like CO2, K+, PO4 etc

I dosed over 3x the NH4 dosed to this tank(0.8ppm a day) in a
non fish /critter populated tank with ammonium chloride.
The plants grew well, not good enough to suggest it was
better/worse than NO3 dosing. Some plants might have a
preference, none that I ever noted with the species used(about
30). I did find better algae control with less NH4 and pure NO3
dosing and no plants had any issues related to poor health from
such dosing with purely NO3 and no fish/critters where present.
This was at 5.5 w/gal of PC lighting. I did this in response to
another person I've lost track of. They have done this with
daily 80% water changes with good results also.  
and that is the catch, the higher NH4, the more you had plan on
doing more water changes.

This is also why heavily fed brood tanks in breeding facilities
often get daily water changes like Discus etc.

Alan recently showed off his tank, he had BBA for some years on
the wood in a heavily fed large fire eel tank(they are as big as
man's arm, 3 of them and lots of other large fish).
He switched to automated water changes at about 30% per day. 
The Java fern is doing great, the BBA died off. There's
virtually no algae, the tank is partially planted with only
ferns on wood.

Fish sources of NH4 are good, but we find even without the fish,
the plants still do marvolus.
Simply take the fish out and dose the KNO3.

Algae etc are less of an issue with KNO3 as well.
Some plants may gain from more NH4, how much? Probably not as
much as many might led you to believe.
I think simply having soem supply of N is more important than
the particular source based on what I've seen dosing both forms
and doing progressive critter additions till i get a bloom.

High fish loading and NH4 dosing can be off set in terms of
algae blooms/issues by daily water changes if you are
interested. Note: many young fish are extremely sensitive to NH4
as are most shrimps.

If you kill them, do not cry about it. 

Regards, 
Tom Barr

www.BarrReport.com



 
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