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Re: Substrate experimentation

Hee Ming, Poh recently asked for input on his ideas for substrate

Your ideas sound basically fine to me - there have been many published
studies in TAG which have used a variation of your ideas, and they got
interesting and worthwhile results, so go for it. You might want to make
sure that the PVC tubes are sealed at the bottom and forget about drilling
holes in the sides - I would imagine that you would want to avoid, as far as
is possible, any nutrients in the test substrate from leaching out into the
water column and affecting the plants in the other pots. Having holes in the
pots would defeat this.

If you want to study the effects of various substrates, there should be no
need for gravel in the tank itself, a bare bottom tank should let you move
the PVC pots around easier.

When doing growth studies, it helps to be willing to sacrifice the plants at
the end of the study - that way you can weigh them first (before you plant
them) and then weigh the grown out plant at the end (roots included, after
they have been washed free of substrate). this gives you an objective
"number" which you can use for comparison purposes. Taking before and after
photos of the plants are also useful, especially for comparisons of root
mass. Having good photos to show also helps if you can't identify a
problem - someone else might be able to help from the pictures.

It is very difficult to set up 2 or more IDENTICAL tanks - but if the plants
are all in the SAME tank, it is easier to assure that the conditions are the
same for them all. You might have to rotate the plants around within the
tank during your experiementation to make sure that local conditions within
the tank don't affect the results.

"- is this too silly an idea or shld I just stick to setting up different
tanks with different substrate"

Get over this one really quickly - don't let anyone else tell you that your
ideas are "silly". Diana Walstad's book Ecology of the Planted Aquarium as
well as her many articles in TAG over the years have detailed a number of
esperiments which could be conducted by any careful hobbyist. Nobody calls
Diana silly.

While your results might not be the same as someone else's, they will tell
you how plants do in your particular setup - i.e. water, light, fertilizer,
so they could be very valuable to YOU as a hobbyist. Go for it!

James Purchase