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Re: Substrate heating

While I remain unconvinced about the absolute _need_ of substrate heating
cables in plant tanks I do have them in my biggest tank but can't say if
they have made a difference, one way or the other.

However, I have recently come across some information which might be of
interest to the "debate". If you read the _many_ threads in the archives
(and elsewhere) concerning substrate heating, you occasionally see reference
made to the fact that in nature most plants grow with their roots stuck in
the "cold mud" (my phrase and emphasis). Why would they need or benefit from
warmth coming from below?

Dave Wilson, a fellow APD'er from down under, does a lot of mucking about in
the Northern Territory of Australia, looking for aquatic plants. He takes
good field notes and recently shared some with me about his efforts to find
and grow Ondinea purpurea, a species of water lily which is found in those
parts of the world. In his notes, Dave makes mention of the fact that in
Darwin, which is located at 12 degrees South of the Equator, the temperature
of the ground at a depth of 1 meter, is 34 C, all year round. Water
temperatures can vary from 24 C to 30 C, with 28 C being recorded at the
collection site, which is in the Kimberly, at 14 degrees South. The climate
is hot and dry in summer and hot and wet in winter. The plants were found
growing in a coarse sandy substrate which overlay red iron-bearing rock.

So, at least in this case, the substrate _is_ apparently warmer than the
overlying water column, in some locations.

[Sounds a lot like a section from The Optimum Aquarium, where they describe
streams containing Crypts.]

Dave describes Ondinea purpurea as the most difficult and frustrating
aquatic plant he has tried to grow and suggests that perhaps substrate
heating might be an important factor in achieving success with the plant.

While an aquarium environment is not the same as a natural one, we can and
do learn from Nature. Information gathered by people collecting aquatic
plants in the field can prove very interesting and helpful to us as aquatic

James Purchase