[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

zinc and driftwood in aquariums

Almost all woods will release some amount of complex, assorted organic
acids (also called humic acids) when submerged ranging from a little to
a LOT. You should also be concerned about the type of drift wood which
you pick up because some types such as cedar are toxic to fish. I don't
know enough about wood to tell you which are the safe kinds but I do
know that Mopani wood which is often sold in aquarium stores, is a heavy
wood and releases _relatively_ smaller amounts of humic acid.

Another alternative is to find some aquarium club buddies who have been
harvesting submerged tree stump roots from lakes. Because these have
been underwater for several years, they may be more stable however, if
they are soft and punky, they're probably not suitable. You also have
the advantage that these folks have probably already tried out the wood
and know what kinds (hopefully) are toxic.

When you use any aquatic material (rocks, wood, mud) which you collect,
it is a worthwhile precaution to sterilize the wood for algae,
particularly filamentous algae and aquatic creatures which can
potentially be quite destructive in your lovely planted aquarium.

As for using ZINC in your aquarium to weight down driftwood, I think
this is a BAD idea. Zinc is soluble especially under acidic conditions.
I don't know how toxic it is but I suspect that similar to other heavy
metals, it may not be good especially for invertebrates and certain
plant species. Instead of zinc, you should use slate. It can be drilled
and attached with steel screws. To initially hold down my chunk of
mopani wood, I just laid a 6"X4" chunk of slate over one of the mopani
roots. After a month or so, the mopani is probably water soaked enough
to sink on its own. This is an extremely dense, heavy wood and easy to

Steve Pushak
Aquatic Gardeners Association  in Vancouver