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Steve wants to "tweak" me???

Steve P. recently re-joined us...

>I've been slowly catching up on the old APD issues I haven't had a
>chance to read since my move and couldn't resist tweaking James on this

Welcome back Steve, hope the move went well. But about the "tweaking" -
careful fella, I'm not that kind of guy... Do you live in the West End of
Vancouver by any chance??? <g>

>Laterite can also create red, cloudy water if improperly used. I presume
>this is what you mean by _colloidal_  solution. Some but not all
>lateritic soils are claylike in texture. The term laterite refers to
>composition, the term clay refers to texture. So your statement is like
>saying not all round things are red!! so?

And a rose, by any other name, would smell as sweet...

I've never experienced any problem with red, cloudy water using Dupla
Duplarit G. It is a granular product not a powdered one. It is much too
early in the morning to play semantic word games - what is your point? I
stand by my statment that an aquarist is much less likely to run into
colloidial fouling of the water column using Duplarit G than kitty litter.

<SNIP> - cut out a description of laterite's properties

>Here I have to ask my question. Why is being highly leached important?
>Why is being highly leached under tropical conditions over geological
>time important? Surely this will cause the LOSS of almost all the
>nutrient value of the soil! Perhaps the only important thing about the
>laterite leaching is thus, the LOW concentration of phosphates and
>nitrates??? Why even pottery clay and kitty litter have this quality.
>Surely the leaching for thousands of years is not critical to this

In my original post, I gave a URL to a reference. Did you follow it? In case
that you missed it, here it is again - http://www.dupla.com/e037.htm. From
an agricultural perspective, laterite is certainly considered an infertile
medium. But we are not growing rice or corn. We are growing aquarium plants,
in small, enclosed boxes, where we (usually) don't have the luxury of
thousands of gallons of fresh water flowing past every minute, carrying away
anything leaching from the substrate.

The most important nutrient supplied by laterite apparently is iron, which
is released from it under reduction conditions in the substrate. I would
venture to guess that what is leached out of the laterite over the
"geological" timeframe referenced by Horst could be aluminium and other
potentially toxic metals. Whatever is missing, we are concerned with what is
left - and it seems to work well enough for growing aquatic plants.

I would venture to guess that Horst and Kipper (Dupla) recommend laterite
based upon their measurements and observations in both the field and in the
lab. They noticed a particular physical phenomenon in multiple tropical
streams and disovered it's source - laterite. Their testing in the lab
confirmed that it works in an aquarium. Their publication of their results
in "The Optimum Aquarium" got the word out, and their company made a lot of
money. The only thing missing from the classic "American Dream" is the lack
of complete secrecy and over-hyped advertising claims (anyone remember

Steve, your wife has family in the Philippines and I believe that you have
said that you visit there every couple of years. I, and I'm sure a lot of
others, would love to hear what you have seen in the the brooks and streams
there - what is the substrate material found in places where lots of aquatic
plants grow?

As I type this, I'm looking at a tank setup using your HTBASS method.
Several days ago, I finally worked up the energy to trim some of the massive
over growth of the stem plants in this tank. I uprooted a lot of plants in
the process and they all had extensive root systems. I didn't encounter any
major problem  with clay particles clouding the water column. But I did
notice a very stong "tint" to the water - tannins are still leaching out of
the soil layer. The topsoil used was a very dark, sandy topsoil over a layer
of clay subsoil. I perform 20% water changes per week on this tank and it
has been running for four months. The tannins don't bother me visually, nor
do they seem to bother the plants or the fish (Cardinal Tetras, Dwarf Neon
Gouramis and Dwarf Rams). From my experience with this setup so far, this
substrate is only now beginning to come into it's own - initially some
plants (Hygro) just wouldn't grow well, but now this problem seems to have
been overcome.

My only comment is that I followed your directions to the letter, I didn't
take any short cuts. Many times, when I respond to a post (or when anyone
else responds to a post...) it is from someone who is considering trying
something new but they are thinking of possibly making substitutions or
varying the mix a bit, hopefully to improve it. Innovation is very
important, that's how we move forward. But equally important is recording
your actions and reporting honestly on your results.

I've never used kitty litter as an aquarium substrate. I have put a cup of
it in a beaker of water and I did observe a major "problem" with collodial
clay particles becomeing forever suspended in the water column. It's not a
substance I'd care to have in the bottom of _my_ tanks. I was able to "wash
out" the suspended particulate, and I was left with a fine grained, dense
(it sinks and stays "sunk") material which could be of great use (I suppose)
in an aquarium. but when I suggested it on the list, several people
commented that I had gotten rid of the "good bits". The CEC had gone down
the drain so to speak. But then again, I'm still not convinced that CEC is
anywhere near as important as some people seem to think.

I've said it before, and I'll say it again.... many roads lead to Rome.
Which one you choose depends on how good a driver you are.

James Purchase