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> --- Sandra Derrick <mygenericemailname at yahoo_com> wrote:
> > I wanted to get some imput on a substrate heating idea
> > based loosely on a Karen Randall design; using a u.g.
> > filter plate covered in a nylon to prevent substrate
> > particle loss, I would have a chamber added to one lift
> > tube large enough to house a submersable heater, the top
> > of the tube would have the outflow hose from my canister
> > filter fed into it creating a downward flow into the u.g.
> > plate. the oposite end would have a small powerhead on
> > the lift tube creating "lift" which sould cause the warm
> > water to flow under the plate and back into the aquarium-
> > the powerhead would be about half way to the surface and
> > would not have the venturi added, so it wouldn't create
> > too much surface disruption, only a bit of movement in
> > the water itself. Don't know if this will work...let me
> > know what ya'all think.
First, I'd like to point out that this is NOT "my" system, nor did I ever
claim that it was. It was suggested to me by Claus Christensen of Tropica
as a low-cost alternative to heating cables a NUMBER of years ago. Please
try to keep attributions straight. Also, remember when you read things on
the internet, that things tend to stay out there for way longer than the
ideas may be current. When I first wrote about this method, it was in the
early "Dupla Days" in this country, when few people had experimented with
different methods of substrate heating, and we we didn't have any where near
the experience level we have now.
In defense of the system, (which, BTW, I no longer use) it does do exactly
what Claus said it would do. In a cold room, very often the water in the
substrate will stratify. It is much easier for water to mix above the
substrate than within it. A regular UGF moves water much more quickly than
we would want in a planted tank, as would the design proposed above. The
method Sandra proposes will move water too quickly, just like a regular (or
reverse flow) UGF. If you use laterite, the result will be a mess. Even
without laterite, ideally we want a reducing environment in the substrate,
not one charged with highly oxygenated water.
The UGF/heater method that Claus suggested does not use a big heater, or any
special "chamber". It is simply a very small, low-watt, non-thermostatic
heater (the ones I used were 7.5W heaters meant for betta bowls) dropped to
the bottom of the normal UGF uplift tube. You don't WANT a larger space, or
you wouldn't get the convection current to pull water up the tube. This
works just like the chimney in a fire place.
I will tell you all again my experiences when I first tried it. It DOES do
exactly what Claus said it would do. It integrated the water in the
substrate with that in the water column, so the temperature was the same,
and no longer stratified. I measured the temperature a number of times, and
it was exactly the same under the substrate as it was above. (There had
been quite a temperature difference before installing the plates, because
the tank was in a fairly cold dining room)
Now the big question is, did it improve growth? The answer in my experience
was no. But then, neither did heating cables when I tried those.<g> I had
good growth before using either of these methods. I continued to have good
growth with them. In the tanks I've set up since then I have reverted to
not bothering with any type of substrate heating. They work fine, and are
ALL long-term tanks. My "newest" tank is over 3 years old at this point.
I've had tanks running and healthy for as long as 8 years without any sort
of substrate heating. When I have taken a tank down, it has never been due
to a "problem" in the tank, but because the tank had to be moved for one
reason or another.
There are a (very) few people who still swear by substrate heating. Most of
us have found that it just doesn't make much (if any difference) and don't
bother. As other people have suggested, I WOULD recommend insulating the
bottom of a tank that is kept in a cool room to prevent stratification as
much as possible. This is easy and cheap enough that I see no reason NOT to
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