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Re: CO2

Elizabeth Worobel <eworobe at cc_UManitoba.CA> wrote:

> Frederik;
> Ten or fifteen years ago everyone talked about how aquatic plants were
> iron limited in an aquarium... all sorts of strategies were developed to
> ensure an adequate supply for the plants and an inadequate supply
> for the algae. Four or five years ago the focus switched to
> nitrogen and phosphorus and the consensus became that limiting phosphorus
> in the water column and supplying it to the plants via the sediment was
> the one true path to success. Lately, CO2 advocates have become preeminent
> ... the same language that was used for iron, nitrogen and phosphorus is
> now being stridently proclaimed whenever CO2 is discussed.

I am not disagreeing with this, but it gives me the impression that the
whole history of planted aquarium keeping was driven by fads. Fashionable
ideas that dominate the picture for a few years and are later replaced 
by some other fashionable idea, all of them with no real value. Of course 
there is a big "fashion" component, driven by, and for for the  benefit of, 
the aquarium industry. But I think the real driving force behind the history 
is _technology_. In particular technology derived from the marine and reef 
aquarium industry.

I'm no expert in this and the experts can chime in, but I think in the 
past planted aquariums where in general more like Diana Walstad's "low tech" 
approach, where the emphasis is on the substrate. The focus shift from iron 
to macronutrients could be just due to the fact that iron is more likely to 
be missing than N and P, due to the presence of fish. So it is the first
thing to notice when an imbalance occurs in a "low tech" tank. Once you get 
the iron problem fixed with affordable and easy techniques such as laterite 
and other prepared substrate additives, you start to notice the macro 
imbalances. Then the lighting technology develops to a point where really 
high light planted tanks become feasible, affordable and widespread. 
Lighting technology driven, of course, by the marine aquarium industry. 
Then you start to notice the CO2 imbalance caused by the bright light. At 
the same time, CO2 injection becomes widespread in the reef arena and 
equipment becomes affordable. And so on. What I see here is just a 
technological development, of course with the full blessing of the aquarium 
companies... The end result is that today average people with average 
budgets can keep stunning planted tanks with difficult species, thanks that 
15 years ago would require a hobbyst with decades of experience and a hefty 
bank account. The hobby becomes more democratic.

> What you need to remember is that aquatic plants exist and grow quite
> aggressively in the natural environment with no supplemental CO2 at
> all. The place to start is with a fertile substrate and adequate
> light. All the rest comes later as you become more practiced in observing
> the health of your plants.

Right, light and substrate are the first things to focus on. But I remember 
hearing this argument every now and then thrown in at discussions about 
artifical CO2 injection. Our planted aquariums cannot be compared to
"natural" environments. They are highly artifical little water boxes where 
one attempts to reach a specific equiibrium state where only the desired
organisms thrive and the result is a show piece that can sit in the living 
room. In nature, plants thrive but the result is normally not showable in 
the living room. The thrive to their liking, not to ours. To achieve the 
desired results, extra CO2 _is_ required, either from  a steel bottle, a 
pop bottle, or a roting substrate. 

- Ivo Busko
  Baltimore, MD