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

Re: Heating cable benefits?

>Date: Mon, 19 Oct 1998 11:17:18 -0400
>From: krandall at world_std.com
>David Webb wrote:
>>Also, knowing that the
>>substrate on these tanks does not deteriorate in the way that it might in
>>tank without heating cables...
>Are we sure that's true?  I believe that George's tanks with cables have
>good longevity.  I also believe that it is good to have a tank set up in
>such a way that the substrate stays at least as warm as the rest of the
>tank.  I don't remember whether George has talked about longevity of tanks
>w/o cables that didn't have a UGF. I _think_ that his non-cable tank had a
>I have yet to have _any_ substrate "give out" in a planted tank.  So I'm
>not convinced that tanks without cables can't have very good longevity
>also.  So far, my oldest substrate is 7+ years.  It's not having any

I don't have any tanks as old as yours Karen, and although I've had
decline, it was on a tank with no nutrient additions at all for over 6
months and no substrate additives.  I remember reading about decline on
rec.aquaria prior to the creation of this list.  Perhaps I'm confusing
compaction with decline in some cases.  I went ahead and included two
examples of decline, one that I found and one that I remember.

In George's articles on the Krib, he mentions four tanks.  A 55g with a
UGF, an 85g with a UGF and CO2 injection, a 100g with a trickle filter,
laterite, and no heating cables, and a 90g set up as a Dupla tank.  I think
I remember him saying that now he has several 120g Dupla tanks, perhaps
among others.

I'll just paste what George wrote about his Almost Optimum Aquarium:
"We were unsure about not providing a water circulation mechanism in the
"substrate but reasoned that plant roots would provide oxygen and Malaysian
"snails would keep it from compacting. 
"What we found was that the plants flourished for about a year. At that
time we
"noticed a general decline in the overall appearance of the plants. Nothing
"dramatic, perhaps a little more red algae on the anubias and a tendency
"hair and thread algae to grow a little faster. A slight slowdown in growth
"noticed. After 18 months, we removed all the plants and did a complete
"vacuuming and added some laterite balls. This restored the tank to it's
"previous conditions and we again saw great plant growth. 

I could only spend a little time looking up these anecdotes, and I think
this was the only one saved on the Krib.  I remember back before the
rec.aquaria reorg that someone described a large echinodorus in their tank
that went into decline and revealed a large, black, rotten, decay pocket
directly under the plant.  I think I remember that they were not using any
form of substrate heating.

It looks like all the nutrients in George's substrate were consumed.
Perhaps in one of Steve's mud tanks, this wouldn't have happened as
quickly, but it would still happen eventually unless steps were taken to
prevent it.  PMDD may be a sufficient step to prevent any form of decline.
However, based on what we know about transpiration and temperature, it may
be possible to make a tank with smaller nutrient reserves recharge its own
substrate.  If this is true, then by definition, the complete Dupla method
also takes sufficient steps to prevent decline.

All this talk really makes me think seriously about moving my ballasts
under my tanks.

>From: Erik Olson <erik at thekrib_com>
>Subject: Re: Aquatic Plants Digest V3 #596
>> From: "David W. Webb" <dwebb at ti_com>
>> Subject: Re:Do substrate heating coils fertilize the substrate?
>> Transpiration occurs, carrying water and nutrients from the roots to the
>> leaves.
>> Heating cables warm the substrate and thus, the roots.
>> Warmth increases metabolism.
>> Increased root metabolism means faster root growth.
>> Increased root metabolism means faster transpiration.
>> Faster transpiration means more water and nutrients move from the roots
>> the leaves.
>David, An interesting hypothesis, and IMHO a bit of fresh air in this
>otherwise gruelingly old topic! One practical note: If this is true, then
>one should be able to get identical results with both cables and flat
>heating sources such as heating pads, ballasts mounted underneath the
>tank, etc.

I don't think the results would be identical.  With the ballast under the
tank, you wind up with a slightly warmer substrate (warm feet), which will
increase the plants' root metabolism.  With heating cables, you'll wind up
areas of significantly greater warmth (hot feet) that could potentially
boost the plants' metabolism even further, assuming that areas don't get
hot enough to damage tissue.

George also points out somewhere (I think on his Aquatic Concepts page)
that boosting the temperature increases the rate of reduction reactions.
The temperature increase that boosts the plants' metabolism also boosts the
rate of reactions that they need to pull nutrients out of the substrate as
well as the rate of the reactions that sequester the nutrients in the

I think heating cables will provide a more pronounced effect because of the
localized, more intense warmth.  I think that in this line of thinking, a
ballast under the tank is probably a good idea in the absence of heating

Dupla may or may not be right in their reasoning that convection is why
heating coils help a tank so much.  I don't think this invalidates their
argument that heating coils do help provide circulation through the

David W. Webb
Live-Foods list administrator