Re: [APD] RE: excess and change over time -- or - exercise bikes for Amazons

["S. Hieber" <shieber at yahoo_com>]

Of course, it's a good thing that folks in the hobby keep
advancing their knowledge.

I think most folks that are concerned about plant nutrient
levels are concerned about promoting undesirable amounts of
algae. Insofar as that's not an issue, I still doubt that
the amounts folks would be intentionally dosing would be
harmful to fish. And I don't think anyone has suggested
that overfeeding plants is inherently bad -- "Hey, my E.
bleheri is overweight". Well, okay, there were some posts
about potassium excesses a few months ago and too, some
folks do think plants can be overweight -- "This need to
prune all the time is too much work."

Just to see what happens, about 6 months ago I started
dosing a couple of my moderately lighted (less than 2 wpg),
no-added CO2 tanks with roughly the same amounts of PO4,
NO3, and trace mix that I put in my highlight, boosted CO2
tanks -- very roughly and in round figures, 1 tsp KNO3/100g
and 1/4 tsp KH2PO4/100g thrice weekly. I still only do a
water change on those slow grow tanks only every couple of
months or so -- e.g., only two water changes so far this
year. It hasn't generated any algae problems. There is an
increased rate of growth of dust on the glass but that's
only one tank and so not attributable (or not solely
attributable) to the dosing.

The dosing hasn't promoted a lot more plant growth either,
but I surmise that the nutrient intake by the plants is
limited by the lighting and CO2 levels. So, I wouldn't
generally recommend these dosing levels for this kind of
tank setup -- at best it's a waste of nutrients. At worst,
I would guess that, if something does trigger algae/spore
production, there are plenty of nutrients in there to feed
them and cause a bloom. What might happen then to create
such a trigger? Hmmmm, perhaps a summer power outage, which
knocks out the lights and filter long enough to allow NH4
levels to spurt up before the power comes back on.

Scott H.

--- Thomas Barr <tcbiii at earthlink_net> wrote:
> > Well, I can only repeat what I learned from Tom Barr.
> But I
> > think his view has changed over time. 
> >
> > sh
> > --- Thomas  Barr <tcbiii at earthlink_net> wrote:
> > > 
> > > >>TB: "Which begs the question: what are excesses?"
> > > 
> > > >The flip side of that is: Once there is 'enough' why
> > > does 'more' do any good?
> > > 
> > > >TW 
> 
> Intially, I was very conservative about advice. But
> privately I was adding
> a lot of ferts back close to 8 years ago at these levels.
> After awhile, I noticed that as long as I kept some
> nutrients in good
> shape, that I could a lot of ferts with no issues.
> It started with getting folks not to fear PO4,
> fortunately everyone pretty
> much no longer fears PO4 on the web. Folks where adding
> K+ without issue.
> Next was Traces and keeping some NO3.
> But why does NO3 have to be kept low?
> What range of GH can we have? Those are nutrients and can
> be extremely wide
> ranging also.
>  
> Why are excesses bad? Do they make plants grow less?
> That does not make sense .........unless you get really
> really high
> concentrations.
> 
> These are basic questions, you don't neeed a test kit to
> do test to see if
> general ranges cause issue or grow plants well, if you
> want to add just
> enough, using a test kit will help if the test kit works
> correctly........
> 
> I've changed a few things over the years, most is based
> on things that help
> folks get rid of their algae and improve their plant
> growth, admittedly,
> the levels are in high excess, but that covers everyone's
> tank and light
> levels no matter what they have.
> Adding more assumes no ill effects on the plants, I've
> never seen any with
> all the plants species I've kept. .......and I've been
> looking specifically
> for them for many years. 
> 
> Things have changed over the years, but mainly ruling out
> various
> arguements for allelopathy, High O2 levels, nutrient
> limitation,
> herbivores, water changes/tap water, what range do the
> excesses exist at,
> CO2 levels, light, and differences between plant species.
> 
> Other issues include what common thread do non CO2 and
> CO2 enriched tanks
> have and why they both work and how they respond to
> different nutrient
> levels(non CO2 tanks are not PO4, NO3, nor Fe
> limited-this is easy to test
> for). The various methods all have a common theme that
> allow the tank be
> stable without algae.
> Each method supplies the plant with enough nutrients for
> a given growth
> rate but all methods work well for the same reason.
> 
> So what happens if you dose NH4 (say 0.5ppm) and do daily
> water changes of
> 50%+?
> It does not cause algae. So why? (I know)  
>  
> Regards, 
> Tom Barr
> 
> 3rd annual Plant Fest July 8-14th 2005!
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>  
> 
> 
> 
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