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[APD] Fertilizing the substrate vs the water column

Mark wrote:

>The implication of an earlier message was that someone who 
> still fertilizes the substrate is hopelessly lost in the past.

Hi Mark, 
This is directed at the statement,nor is meant to be at you,
just in general.

Nope. In reality, most every aquarist does substrate and water
column fertilization with some nutrients.
How much is the the main issue. 

Some folks still, even to this day, want to support excess water
column nutrients = algae. This was blown entirely out of the
water a decade ago or so.

Hopelessly lost in the past in that respect, this part is true
as a form of justification for the dosing method. Some get good
at one method and obviously feel enamoured and bias towards it,
it's working for them. But learning how to use both and the pit
falls and trade off involved is very useful info. You need to
see both sides of the coin.  

The information is out there and any one wanting to prove it to
themselves can do the dosing and see. Plenty of folks have long
seen this(excess not = to algae) observation for many years.
That hypothesis for algae blooms cannot be correct(except with
respect to organic loading=> high fish loads, NH4, both somewhat
similar reasons).

As far as a conveinent method for lower(or higher) light tanks,
that is a good justification. As far as a method to supply
nutrients to the roots without water column transport, that is
also a good justification. As far as textural differences and
easy to use NH4 sources for plant roots that do not get into the
water column, that can be a good method. As far as a cheap
method vs the pricy designer substrates, it's a decent method.
As far as a method to provide more wiggle room in the water
column dosing routines, it's a good justification.

It's also a very old method.

Nothing wrong with keeping it.....
But.............rather than this "either or" baloney........

Combining it synergistically with a good water column
fertilization routine would be ideal.
The methods are not in opposition.
They both supply nutrients, just in different locations.

Adding water column ferts enhances the efficacy for the
substrate ferts and extends the life/supply of the substrate
ferts, as well as allowing many non substrate rooted plants
ample supplies.

Likewise, adding substrate ferts will reduce the need for higher
levels of water column ferts should that be your thing(this is
certainly not required nor needed), or if you forget/neglect to
dose once, twice etc. This provides more wiggle room for either
method of dosing.
It also allows for the excess side of the water column as well,
does no harm nor causes algae etc if there's excess in both
locations. As the substrate becomes depleted, the water column
ferts will maitain good growth still.

Now some have suggested that terrestrial plants do not take up
foliar NO3 or nutrients through their leaves other than say CO2
etc or gas forms of NH3, I'm not sure how much farming
experience you have or not, but foliar fertiliers are very
common in many crops. They work well and plants absorb the

Like the water column ferts, they have a similar impact, rapid
growth but not long lasting unless you keep applying it(say like
EI dosing 2-3x a week). NH4 at high rates will burn and kill
crops, so they typically use very low amounts of that and use
high rates of NO3.

Just like in our tanks............
While many like to think about the differences, and that is
good, there are other fields that allow us to see the
observations and make some test and conclusions.
An aquatic or a terrestrial plant may be in or out of the water
at some point, flooding in many areas is common(especially when
it comes to the amphibious nature of most aquatic plants), so
having access to both sources would be a good advantage.  

But having higher excess nutrients in the water column is not
bad, as many folks seem enamoured with suggesting/claiming for
fish(NO3), or with algae(NO3, PO4, Fe).

I've done these test with many species of fish and plants and
algae. There's nothing in the observations I've done to suggest
any of it is true till you get over 100 ppm NO3 and then only on
shrimps, I'm sure there is an upper range for fish using KNO3,
but I've not yet found it at 3 days exposures up to 160ppm. 

I've never been able to induce algae with NO3/PO4/Fe at any
concentration, the ranges are so high that other toxic effects
with fish, shrimp will influence the system. 

I've tried very hard over the years to show folks this.

Note, many make the poor assumption that excess fish waste and
the end product NO3 are the same as adding NO3 from KNO3.
They are not the same.

Sadly, such folks that make such claims seldom have much hard
range data or specifics when it comes to supporting their

Often it's some long held myth they want to believe or read many
years ago and the idea stuck and cannot be removed. They often
will not test and see either. There is a very strong correlation

So those are stuck in the past I guess one could say and are
held back by their own assumptions. Fish waste starts off as
something quite different than KNO3. Assuming they are the same
is a poor assumption.

Many do though, it's a normal basic question, "why can I not add
more fish to provide the fertilization for NO3?"
That's another post. But folks can look into this more on their
own or search.

Plants will still grow with substrate ferts, obviously they do
add traces and CO2 and Ca/Mg and then there is fish waste,
but......they could do it one better and have either method work
better by combining both of them, not just one.

By isolating each method as best folks can, then seeing what
each offers, you learn a lot.

Then you can go back and see what trade offs each method has and
how this can help the aquarist.

Some folks like a low tech no/little pruning, neglected tank
method, they have no need to grow stem plants like mad, non CO2
methods work well for this.

Some love the Riccia/Tonia tanks and like to prune weekly, some
like a grade in between.

By understanding what each trade off and mechanism each
method/location are method has, you get a much better
understanding over all.

You also realize much of the misunderstandings between each
method are myths. I suggest folks really interested in methods
to try out both the CO2/non CO2 methods, they are often very
surprised as a result.

Such techinques, methods and knowledge allow the aquarist to be
less limited in their approaches and achieving goals.

This provides more flexibility than what many may suggest.
It'll also save you a huge chunk of $$$ as well as give folks
some fun test to play around with, or not, they can simply grow
plants easily and mess with scaping etc.
It also reduces the wild goose chases many do worried about
excess nutrients, using PO4 removers, having to do many water
changes(non CO2), worried about doing large water changes(CO2)
etc or adding this month's latest snake oil miracle algae cure,
plant growing concotion on the market.

15 years ago folks had a much tougher time, info was scant at
best, so we have come a long way from just the substrate fert
methods and folks have far more options, better growth, less
algae issues.

Algae is often due to lack of nutrients, poor plant health,
limiting the plant growth, lack of plant biomass at the initial
planting stage and every so often excess NH4.

But folks have also started using 2-6x more light over this same
time peroid:( Ugh.
That makes it harder to maintain any method, and less light will
slow down plant growth at the source, not to mention costing
less. Folks had nice looking red plants with those 2-2.5w normal
output FL bulbs back then as well.

So hopefully over the next 15 years, folks will reduce the
lighting and switch mainly to HQI and T5's at these
wattages(1.5-3w/gal) and try out more non CO2 planted tanks as
well as the CO2 enrichment.

Tom Barr





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