On Thu, 27 Apr 2006 18:51:12 GMT, Altum
wrote:

Limnophile wrote:
"Altum" wrote in message

Undergravel heating isn't as popular as it was 10 years ago. People who
have tried it say it doesn't make much difference. I would spend money on
a good laterite substrate instead.

--
People have a variety of opinions on undergravel heating cables. I've seen a
few planted tanks with the undergravel heating cables, and the plants were
very lush and beautiful. On the other hand, they may have done just as well
without the cables. The theory is that heating the bottom of the tank causes
more water flow through the plant roots, increasing the amount of nutrients
available. Does anyone here have results from any experiments to support
whether it improves growth or not ?

Horst and Kipper did the experiments and found improvement. They talk
about it in the Optimum Aquarium. Tom Barr (a well-trained plant
physiologist) has done carefully controlled experiments and says he
found no differences. George booth found differences but only after a
few years. Plant growth slowed some in his non-heated tanks. Diana
Walstad addresses them in her book but I'm waiting my turn to borrow a
copy to read. Have you seen anything from Amano on cables? I know his
ADA line doesn't manufacture them.

The cables certainly won't harm a tank.

Every time I plan a new "big" tank, I consider undergravel heating
cables. My pocketbook usually makes the decision for me, but there
have been times, like my current plant tank, when I saved for a year
and vowed to spend whatever I needed, but I still didn't go with
cables. (At Christmas 2004 I announced that for Christmas 2005 I would
get my dream aquarium.) The theory behind the continuous convection
currents of heated water rising through the gravel makes sense, but I
always come back home to: The strongest convection currents that can
be produced are going to be immediately destroyed by all of the other
currents going on from my one or two power or canister filters as well
as simple fish motion and the not so easy to measure currents created
along all 4 glass walls with the 15 or 20 degree difference between
the room air and the water temperature. I've placed regular back ache
type heat pads under tanks on top of beadboard in the past, waterbed
heat mats are much better for this because they can be
thermostatically controlled over a wide range of temperatures. I
honestly thing that the best bang for my buck has come in the
investment and time devoted to a healthy clay based substrate and
conscientious feeding and maintenance, (pruning, snipping and
replanting tops of stem plants, etc.). I've always placed my tank
heater horizontally about an inch above the gravel, that simple
placement provides a bottom to top convection wave of sorts. In my
current large planted tank, I am using a heater inline in my filter,
so the heater near the substrate may have been as useful/less as under
gravel or under tank heating. A waterbed heat pad runs around $60,
last time I checked, and is pretty close to the size of the bottom of
a 55 gallon tank. I use one to start my seedlings for my gardens in
the spring. It is from one of the old waterbeds that I have since
gotten rid of. I only wish I had saved the heaters from the other
three water beds we got rid of.

-- Mister Gardener
-- Pull the WEED to email me