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Re: CO2 or not CO2

Roger wrote:
> Wasn't Jame's original intent to compare different substrate recipes? 

If you want to really study the difference of the substrates, you need
to isolate the differences of the water nutrients. I think James would
like to conduct a controlled, scientific experiment. I made the point
earlier to James, that if he were simply comparing three or four
different "recipes", then the degree of success that he attained with
each recipe, would really only correspond to how well he had mastered
each of those recipes.

James really needs to carefully define the objectives of his experiment.
For example:

If your objective is to find the plain and simple "easiest" no brain
power required approach without regard to the cost of equipment and
supplies, and you wanted a tank with rather slow to moderate growth
(reserving the term high growth for doubling times of 2-3 weeks or
less), nice looking plants, little algae, then you could probably go
with The Optimum Aquarium approach and buy a lot of nice Dupla products.

If your object was similar but you wanted to save money at every
opportunity and were willing to invest a little time in studying, I
think you might choose a subsoil + peat approach with little or no
additional substrate fertilization.

If your objective was to specialize in Crypts, I think you -might- want
to experiment with soil and peat substrates and probably use clay and
fertilizer supplements.

If you wanted to grow very large plants quickly (for sale), you might
choose to use a fertilizer supplement in the substrate.

It really all depends upon your objectives. I do believe that a beginner
can learn to use a subsoil substrate fairly easily and that these are
just as easy to use and master as other commercial substrate amendments.
Rich soil substrates are not for the beginner I do agree.

> If I
> remember right, some of these recipes are part of a more comprehensive
> fertilizer regimine.  Tetra, for instance, sells Initial (substrate
> amendment), Hilena Crypto (substrate fertilizer) and FloraPride as a
> complementing set of substrate and water additives.  To test the recipe
> James would have to follow the whole course prescribed by the substrate
> proponent or manufacturer, not mix and match fertilizers with substrates.

Yes, but how do we compare these different methods fairly?

> Few if any of the aquatic plant fertilizers carry much N or P, as those
> are provided in abundance by fish food.  Maybe N and P are all that James
> should add to make up for the lack of fish.  If a substrate/fertilizer
> combination is lacking in something other than N or P, then it should
> appear in James' tests.

Yes, N & P are going to be important to the study. I suggest using a
pure nutrient solution of known composition. Another alternative to
keeping fish in the aquariums that I suggested to James, is to take a
few litres of water from one of his fish aquariums and add equal
portions of this to each of the subject tanks. The fish food provides a
great many nutrients (trace and macro) and is good for growing plants.
If some of the substrates under study are also low in organic material,
the fish water will provide valuable organic complexes which are used
for conveying nutrient ions.  

Another critique of fish water is that it's not strictly reproduceable.
This is true of any source of organic material including the soil.
Sphagnum peat moss from a given supplier is probably the closest to a
consistent organic material as we can get. Oh well, at least if others
do reproduce the experiment, their data will give valuable insight into
the sensitivity to these other difficult to control factors.

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!!!