ENRICHING NATURAL BEDS
Like a gardener, the aquarist can enrich these natural soils, as the most common
sands, like quartz and Loire sand, are somewhat deficient in mineral elements, and
so there is a danger of plants being affected by this when the aquarium is put into
operation. Remember that it is possible to add both solid and liquid fertilizers
to compensate for this deficiency. Once a good equilibrium has been achieved, the
bed will gradually get richer and will start to be really beneficial to plants after
about 4-6 months of operation.
Hobbyists who want their plants to grow more quickly can introduce an enriched
substrate at the outset. This is available, already prepared, in the aquarium trade,
but you can also make your own enriched bed on the basis of a recipe used and advocated
by countless fishkeepers and specialist magazines (see box below). However, beginners
are advised to start with a normal or commercially enriched bed, before moving on
to create specific individual substrates.
THE BED AND OXYGEN
As a general rule, a bed must be considered as facilitating the movement of water.
The water supplies oxygen to the microfauna living in it, enhancing the progress
of the oxygen cycle. If the sand used is too fine, it becomes too compact to allow
the water to circulate freely. This may give rise to black patches, a sign of oxygen
deficiency and the presence of toxic substances.
MAKING AN ENRICHED BED
The classic recipe is:
- 10% clay: this enhances the use of mineral salts by the plants;
- 40% heath-mold without manure: beware of false heath-molds and various types
- 50% unprocessed Loire sand: if this is not washed, it contains mineral elements.
Mix the ingredients and put a 1 cm layer of quartz sand on the bottom, followed
by 2-3 cm of the mixture and pack down thoroughly. Cover this with a few centimeters
of quartz sand.
Obviously, you will not be able to dig around in this kind of substrate, so do
not forget to put the decor in place beforehand. Do not use an under-gravel filter
with this substrate. It might be argued that it is not oxygenated, as we have previously
recommended, and this is true. However, it does produce other reactions, and accidents
with it are very uncommon. Some aquarists have reported that this type of bed can
remain effective for more than one year, sometimes more than two. Even if you are
reluctant to apply this method directly in an aquarium, it can nevertheless be used
in small aquatic jardinieres containing plants. This certainly has practical advantages
- they are easy to move - but you will have to camouflage the bed.