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Re: A discussion of substrate additives

Here are a couple of messages from Jim Kelly regarding his success
with the vermiculite recipe and some comments on my previous
substrate posting. I'd (mistakenly) implied that one of the possible
constituents of laterite was amorphous volcanic minerals.

jkelly:

Thanks for sending me your substrate posting.  I finally had time to read it.
I just want to make two comments.  First, the amorphous minerals of volcanic
origin are not laterite.  Laterite is composed of mostly Fe and Al oxides, and
some kaolinite, and thus has a LOW CEC according to these ideas!  Second,
most of my recommedations are tenative, since I have never set up a Dupla
tank and don't know how mine would compare.  However, I would say that the
vermiculite/loam substrate with sand on top is the best I've tried.
Unfortunately I must admit that I've been too busy in the past six months
to tinker with my tank or think about optimization.  I only have time for
for routine maintainance :(

Let me know if you have any new techniques that work.

jkelly again:

The volcanic material is called allophane, and as far as I know duplarit G
is pure Laterite and contains no allophane.  I don't know that you shouldn't
be concerned about allophane, I just don't know where to get it.  If you
want to try it you might ask the soil science dept. at the nearest university.
Maybe I'll ask around here (UC Davis) for more info or a sample.  You might
be looking at an old version of my posting, since the newer version uses
the word 'allophane' in that section (you quoted the old version).  If you
don't have it, I'll email it.

Unfortunately I don't have any hard data for comparison with Mr. Booth's
famous method (which clearly works).  My methods are based on the assumption
that the reader is frugal and has no special resources...I have tried my best
to get the best results given these tight constraints.  I don't think plant
growth rate (and quality of growth) is an issue for the heating coil/circul-
ation debate (UNLESS you have a lot of organic matter decaying in the
substrate, which might show up in the long term or if you use organic soils).
I have had phenominal (IMHO) plant growth as long as there is CO2 and adequate
nutrients.  More of an issue is the algae growth and maintainance level.
George sounds like he has this wired.  My oldest tanks of my type are still
only 1 year old, and I haven't torn them down, and there is still good
growth.  That's as far as I know.  Regarding algae,  two of four tanks are
spotless and seem to resist any algae (there is algae in the tank but not
coating the leaves or the glass...it's the thread type and it grows so slowly
that it isn't visible if you hunt for it once a month and remove it).  The 
other two tanks have periodic algae outbreaks varying in severity.  Plants
are shared between the good and bad algae tanks so I know that it's the 
environment in the good tanks that resists algae, not some avoidance of 
innoculating the clean tanks with spores from the other tanks.  Strangely,
the spotless tanks are two 10 gal tanks, and the ones with periodic problems
are the 55 and the 30 gals.  Maybe I change a higher percentage of the water
in the small tanks since it's easier, and that leaads to success.  I don't know.
Anyway, my main emphasis from now on is going to be on constructing low
maintainance tanks, which will mean a lot of smaller rosette plants which
won't require weekly pruning like stem plants do (of course I'll also use less
CO2 since that's part of the problem).  I want stable tanks which I just 
have to do water changes on, not heavy gardening.

I will eventually find out what the secret to the stability/no algae is.
You can post this and the previous email to the news or mailing lists.

Jim Kelly