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Re: bone meal

On Wed, 20 Oct 1999, Steve Pushak wrote:

> I've never tried using bone meal as a substrate amendment in aquariums.
> I use it with my roses and fruit trees. I would wonder if bone meal in
> the substrate might encourage the growth of bacteria?

One of the few references to bone meal in the APD archives is a
reply from Paul K. to a question from a woman who potted some water lilies
in a medium that included bone meal.  He suggested that slime growth on
her lilies resulted from the bone meal feeding bacterial growth.

> I read with
> interest an article in the latest TAG about the problem of excess
> bacterial growth in newly submerged organic soil aquariums. The author
> highly recommended the use of snails and detrivores like catfish
> especially Otocinclus and Plecostomus. The author said that excess
> bacteria can form a slime coating on the leaves of the plants and this
> can severely inhibit their ability to absorb nutrients and light.

"Biofilms" can form on any submerged surface.  Those are communities that
include bacteria, algae, protozoans and often cyanophytes all tied
together in a complex carbohydrate slime.  Our aquariums' normal coatings
of diatoms and green "fuzz" are just variantions of biofilms.  Snails and
fish like SAEs, CAEs and otocinclus that spend most of their time grazing
on surfaces are feeding on those biofilms.  The biofilms are common
(probably inevitable) and the surface-grazers are their natural controls.

> I had
> something of a problem like this when I set up my 50 gallon tank earlier
> this year however after a few months, the slime seems to have
> disappeared. I wouldn't use garden soil in large amounts again since the
> topsoil in my back yard seems to have been quite enriched with compost.
> I've used it in pots in much smaller amounts with good success.

Stable biofilm communities are complex, with an internal balance between
primary producers and consumers.  It's possible that heavy biofilm
development in a new tank is due to early imbalances *within* the
community, rather than (or in addition to) external factors like nutrient
supplies and grazing.

> Roger, why don't you try using bone meal in a ceramic pot with sand,
> clay and peat or some other mixture? It might be interesting to set up 3
> or four pots with different mixtures to compare results. You could also
> experiment with fast and slow growing plants. I think Crypts benefit the
> most from substrate amendment since they are normally slow growing. If I
> fertilize a sword plant in the substrate, the darn things just try to
> take over even with a moderately infertile subsoil substrate.
> As another alternative for providing P in the substrate, I've used
> 14-14-14 Osmocote pellets (10 granules to the ball) in clay balls. One
> of these balls is like rocket booster fuel to most aquatic plants! The
> clay seems to prevent the diffusion of the P into the water quite
> nicely. You could do the same thing with bone meal, mix it into clay
> balls.

I'm thinking along the experimental lines.  It seems like an interesting
winter project. If I were to test with potted substrates then I think the
different pots would have to be in different tanks, so that any phosphorus
that might leak from one pot won't effect growth in other pots and confuse
the results.

Roger Miller

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