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Re: Aquatic Plants Digest V3 #853

James writes:
> Gosh, I'm getting dizzy! Steve P. recently advised a newbie:
> >I suggest that you stop adding the trace nutrients in solution and
> >supply them instead by the substrate.
> In the very same issue of the APD, he said, to Dr. Morin:
> >With a supply of pottery clay and osmocote, its fairly easy to make
> >additions regularly! for several minerals, its simple to add them in
> >solution and no real benefit to adding them in the substrate.
> Come on Steve, make up your mind. Do nutrients belong in the water column or
> in the substrate? Does it differ depending upon who you are speaking to?

The answer to the first question is "yes" they belong in both. and at
times it does depend upon who is getting advise. The primary theme of my
substrate article is that "It depends" ! It depends upon what plants you
want to grow. It depends upon who is teaching you. It depends upon your
personal biases. It depends upon whether you want to learn everything
you can or just use a recipe. It depends if science is intimidating for
you. It depends on if you define "optimal" as minimizing effort or
minimizing cost.

My teaching is: trace nutrients in the substrate. CO2, Ca, K and Mg in
solution. Also P and N can easily be supplied in solution or in
substrate or in both. I don't care. I don't advocate any single
approach. This must be what is confusing you. Perhaps you wish to stick
me in a neat cubby hole?? HA! I rejoice in confusing you then! :-)

> Newbies hit the dirt, PhD's go for a swim?
> In the same volume of the APD, Steve continued with Dr. Morin:
> <Dr. Morin>
> >> The iron in Flourite is different, it's
> >> already in the material and in such high levels one really could do
> >> away with iron supplementation (for some species) and be just fine...
> >> i.e. the plants extract the iron directly from the Flourite through
> >> their roots, none is released into the water column.
> <Steve>
> >That is my finding too; that with available substrate iron (i.e. clay)
> >and with a little bit of peat, there is more than adequate iron for
> >rooted plants and even for floating plants since the peat releases
> >humins which act as natural chelating agents in the water.
> Mmmm, I find this truly amazing. Steve, as far as I know has never used
> Flourite. Are you making reference to the use of Flourite here Steve, or the
> Micronized Iron you add to the soil you dig out of your back-yard?

Greg said he found that Fluorite could provide enough iron for many
rooted plants. 

My findings refer to what I said "available substrate iron (hint, clay)
+ a little bit of peat"

The finding that we agree on is that a "suitable" substrate can provide
enough iron for healthy growth. This makes you dizzy? stop smoking your
plants! ;-)

> I'm not questioning the HTBASS methodology, I've used it myself and it does
> work. But it works well in the hands of a very experienced person. I have
> never, even using a LaMotte low range Iron test kit, been able to measure
> Iron in the water column of the tank I run using the HTBASS methodology.
> Plants rooted in the substrate grow well, floating plants like water sprite
> or riccia don't grow at all. Micronized Iron in the substrate, even with 10%
> peat to help chelate nutrients, doesn't do squat for floating plants, at
> least not in _my_ tank.
> I'm basing my comments both on observation and on measured data. I regularly
> test my water using a Lamotte Iron Test Kit. In the HTBASS tank, plant
> growth is good, provided the plant is a rooted plant. I've never seen signs
> of deficiency in rooted plants, but riccia just rots away in this tank. I
> have NEVER been able to measure ANY iron in the water column.

Are there any humins in the water? Perhaps your test kit cannot detect
the iron at low levels. I assure you that in tanks with peat and
suitable clay, there is sufficient iron in solution for floating plants.

There may be another cause for the Riccia melting. You might have high
Cu or other metals in that aquarium water. It's just a possibility that
needs to be accounted for before you assume that the Riccia is dying for
lack of Fe. Do you think its possible that sufficient iron could even be
below the threshold of detection for the Lamotte test kit?

> Steve continues:
> >Peat could be mixed with the clay and made into small pellets that could
> >be mixed with the fired granules. The product needn't be homogeneous.
> Mmmm, yes, I guess they could be. But why complicate your life? In my

what's complicated? a hypothetical mixture of fired clay, clay and peat?

> Flourite based tank, which uses a 100% Flourite substrate, sans ANY peat,
> but with regular additions of Flourish and Flourish Iron, I can grow rooted
> plants and floating plants, and have never had a real problem with algae -
> at least not since I learned to be stingy with the Flourish Iron (it's
> powerful stuff).
> Bottom line Steve, Flourite doesn't NEED peat, nor any other substrate
> additive, to grow beautiful aquatic plants.

Indeed. Never said it did. I think you're pulling my leg with all this
guff. Aquariums with Fe in the water don't need Fe in the substrate
(hydroponic). Aquariums with Fe available in the substrate don't need Fe
in the water (geoponic). So??? What do you conclude from this?? That we
are all confused and cannot make up our minds about what is needed?

> >I should think you'd want to do some analysis for Cu, Zn, Mn, B and Mo.
> Steve, do you know the values for these nutrients in the sub-soil that YOU
> use? Do you even USE test kits? I'm sorry if I sound snarky here, I really
> don't mean to be, but in ALL of my conversations with you about the HTBASS
> methodology (and I have them all archived), you never once mentioned any
> analytical "testing" that you had done. Indeed, your aversion to water tests
> is well known to the regulars on the APD.

Well I don't test the soil I use from the backyard but then it costs me
nothing to get it. One way to test a soil is to simply use it and if you
don't need to add any trace elements to the water (ala PMDD chelated
trace element mix, TMG, Dupla Drops, etc.) then kewl! It works.

On my web page, I do provide detailed information about where to send
your dirt IF you should decide that YOU want to get it analysed. This
saves time.

Now let's not talk about HTBASS which is about saving money, let's talk
about aquarium products where you have to fork over hard earned dough
because you want guaranteed results.

I would suggest that if someone were to actually pay money for an
aquatic soil, that they would be wise to choose something that would
indicate what was exactly present in the soil. If I were a manufacturer
of a product, I think I would try to attract a market by providing an
accurate analysis of the product's composition.

To the manufacturers: do not think that by concealing the composition of
a soil product in the marketing material, that you are in any way able
to protect the composition from the competition especially if you are
getting the stuff out of the ground. The competition has access to the
same soil analysis laboratories as everyone else. 

So if I were a manufacturer and I was selling a substrate amendment for
a purely hydroponic system because I was also selling all the
ingredients for adding to the water, the only thing that could be really
useful in the substrate amendment would be iron. (bingo! laterite!) Why
sell something for the substrate that is advertised to make it
unnecessary to use one of my other products! And how do I sell the
substrate amendment? I'd sell the IDEA of the substrate amendment.

How do I get dragged into these discussions? I don't have time for it.
You guys bait me into it. >:-[ grrrr

Steve Pushak                              Vancouver, BC, CANADA 

Visit "Steve's Aquatic Page"      http://home.infinet.net/teban/
 for LOTS of pics, tips and links for aquatic gardening!!!