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Sulfide gas around driftwood

Steve wrote:

>In my opinion, hydrogen sulfide and low redox (often inappropriately
>mistermed anaerobic) are the boogie man of aquarium lore. The aquatic
>botanists who study substrate conditions in relation to plant growth (eg
>Barko and Smart) cannot tell us definitively what causes diminished
>growth in correlation to increased organic content. I don't believe it
>is redox related or related to the loss of nutrients. There are numerous
>byproducts of decomposition (alcohols, phenolics, esters, aldehydes,
>ketones and so forth) which are relatively stable and mildly toxic and
>these are the primary cause which Barko & Smart suggested in their
>studies. An accumulation of feces after a year or two especially with an
>UGF might cause such a condition. Just a theory...   :-)
>Some of you should think carefully about what I said in the preceding
>paragraph to see if it supports the assertion that laterite and similar
>stable materials might be more optimal for very long term aquarium
>substrates. I'm not aware of many studies which extended for multi-year
>time periods. Some knowledge is not easily gained.

You've got to give us a clue what we're supposed to think carefully about.
Do I agree that hydrogen sulfide and low redox are "boogie men" in healthy
planted tanks?  Yes.  I've said it before, I'll say it again.  I've never
seen it in any substrate "at large" in any of my tanks. (I have ONCE seen
it in a plastic container with a potting soil substrate and a large A.
madagascariensis... something I now know was not a good idea since these
plants seem to need higher than average O2 levels in the substrate)  I have
also never seen it or heard about it happening in a well designed system
run by another aquarist.  In the few occasions where I _have_ run across
it, there were multiple management problems in the system.

Is your assertion that laterite is more or less likely to cause these
conditions than more complicated substrates?  I'm absolutely positive that
it is possible to run soil based tanks 
on a long term basis without major problems.  I've done it, and I've seen
it done by others.  HOWEVER, without the aquarist having a good
understanding of what they are doing, I've seen more soil substrates "go
bad" (it really doesn't matter whether it's hydrogen sulfide or phenols
that are killing the plants and animals, although it's interesting to
conjecture) than I've seen laterite substrates "go bad".

Incidentally, most of the tanks I've seen that have had serious substrate
deterioration problems were plain gravel substrates in fish-only tanks, or
those where people were "trying out" a few plants.


Subject: didactic postings of mine

Steve wrote:

>I suspect that many of you find my posts too technical for your interest. 

I think many of us turn to this list specifically _for_ more technical
information and for the exchange of ideas among more advanced hobbyists.
Otherwise there would be no need for the APD as a separate forum from

>Some of you may find the information old and it may seem uninteresting. 

While I sigh when I read a query on a subject that has been addressed
numerous times, I personally am glad when someone _else_ is willing to
respond to it.  It saves me from feeling of guilt.<g>  I can always page
down through the response if I don't want to read it.<g>

>Some others of you may feel  the need to defend the truth or perhaps to
provide some sharp >but useful criticism.

Since this comes on the heels of my unanswered response(s) to your posts, I
suspect you put me in this category.  It certainly fits me more closely
than the other categories you mentioned.  I do feel that when we (that's
the collective "we", not the royal "we"<g>) post to this list we need to
take the responsibility to make a clear distinction between scientifically
established fact, person observation and conclusion, and personal
conjecture and/or opinion.  That is only fair to the novices who read this
list and take what the "experts" say as gospel. ("expert" in this instance
can be read to mean those of us who post regularly<g>)

I stayed clear of this whole ball of mud until your comments about laterite
only working as part of the Dupla system, and your, IMO, overly broad
definition of what constitutes the Dupla system.  If this is what bothered
you, I'm sorry, but I call it as I see it.  While I haven't spent the time
reading scientific papers on substrates that you have, (and, BTW, I
appreciate you sharing what you have learned in that reading with this
group) I do have a _lot_ of hands-on experience with a lot of long term
planted tanks, under a range of conditions, with a number of substrate

I don't always know _why_ something works, but quite frankly, I don't think
the scientists have all the answers there either.  But I _do_ know at least
one method that works on a sustainable and repeatable basis, even by the
novice, casual aquarist.  There are probably others, but I have yet to find
one that I feel produces better results in the hands of a novice, and at
the same time is not complicated enough to be daunting.

I'm always "tweaking" how I handle things in my personal tanks, whether to
accomodate a difficult plant, to streamline maintenance or whatever.  I'm
sure you do the same.  You obviously really enjoy your experimentation with
different substrates.  If it gives you pleasure, you _certainly_ should
continue with it.  We can all learn from your successes _and_ your failures
when you share them with us.  

The more I listen to the _experiences_ of other aquatic gardeners, the more
of the puzzle I feel I can fit together.  We've come a long way in this
segment of the hobby in recent years, but _all_ of us are a long way from
learning everything there is to learn.  

Let's all try to share our observations and ideas as what they are.
Observations. Ideas. Theories.  If others have contradictory observations,
it doesn't necessarily mean that the first person's observation is flawed,
but it _could_ mean that their theory on _why_ something happened is
flawed.  That is useful information in itself.  

Let's also be careful of interpreting the methods of others, whether it's
"misquoting Karen"<g> or presenting an overly broad interpretation of a
specific company's "method".  Dupla, in particular, has a very carefully
documented system summarized in their widely published "10 Golden Rules for
the Optimum Aquarium".  IMO, anything outside their published "Golden
Rules" would not be considered the "Dupla Method" by them or by most other

>More people have written to me all the time that I have been posting to
>the APD to thank me for my postings, than ever to criticize. It takes a
>lot of time and effort to write the posts and I have lately considered
>not spending that effort anymore.

If more people write with praise than censure, then you should be able to
take a little criticism too without it upsetting you too much!  We need all
the enthusiastic spokepeople for this hobby that we can get!

A note to everyone else, and I'm sure that Steve will agree completely with
While both Steve and I use "Aquatic Gardeners Association" in our sig. line
as a promotion for a very worthwhile organization, the opinions we express
are our own.  We are not in any way representing the "position" of the AGA
in these discussions.
Karen Randall
Aquatic Gardeners Association