Question: what studies are out there regarding substrate heating?

Has anyone ever set up two duplicate tanks with one difference between them:
one tank with, the other tank without cable heaters? How about something
related: 1/2 the tank with a cable heater, the other without? I am wondering
what the real benefit of these rather expensive accessories are.

If there are no such systematic studies out there, anyone have suggestions on
carrying out such a study? What things would you need to be wary of?

Thanks in advance for any information you can provide. -Bruce Geist

"BruceKGeist" wrote in message
...
Question: what studies are out there regarding substrate heating?

Has anyone ever set up two duplicate tanks with one difference between them:
one tank with, the other tank without cable heaters? How about something
related: 1/2 the tank with a cable heater, the other without? I am wondering
what the real benefit of these rather expensive accessories are.

If there are no such systematic studies out there, anyone have suggestions on
carrying out such a study? What things would you need to be wary of?

Thanks in advance for any information you can provide. -Bruce Geist


There is a good article by George Booth on the topic of substrate heaters he
http://faq.thekrib.com/plant-cables.html

I will now take the liberty to copy and paste here a couple of sentences from
that URL:


***********************
We have three ~100g tanks with coils and one 85g tank with UGF. All grow plants
equally well but the 85g is much more unstable. We think it is sensitive to too
much detritus building up in the gravel; a thorough vacuuming every 6-9 months
perks it up. The coil tanks require no gravel vacuuming and the 90g tank was
rock solid biologically for at least three years. We replanted at that point
because some of the plants had gotten out of control but we didn't "tear down"
the tank - just replanted.
I think this is the key to the cables - long term stability

***********************

Reading the George Booth's article inspired me to get a substrate heater as
well. I set up my 90g with cable heaters but unfortunately few weeks later the
heater stopped working. Now I'm using under tank heating mat which is most
likely not as good as functioning substrate cable heaters.

--
Marvin
hlavac (at) rogers (dot) com

Tropica did one of these a few years ago and found the optimum flow
for plant roots was about 0.49liters/day/m^2
Not much. Cables cause much more flow than this.

I've used cables from Dupla, Sandpoint, reptile heating pads, built my
own cables(7 over the years) and I feel you don't get anything for the
trouble or the money.

I've have done a number of flow rates through gravel over about a
decade.

No flow, osmosis is the most popular and easiest and the best IMO.
Low flow, cables are good but I saw only some added stability in the
start up, the theory behind it and the observations themselves are
weak at best. But it does seem to hurt either.
High flow, RFUG. work great also. I used these for about 15 years and
really like the results in the start up and the long term.

The best substrate I have used and still use is Flourite or onyx sand
with some ground peat and rich vacuumed mulm from an established tank.
That works the best IMO. Never breaks, nothing to plug in , grows
plants the best etc.

Unless you have a closely controlled temperature in your home, the
cables will be shutting on/off etc and that will greatly effect the
flow rates.
Many folks cannot use them in the summer due to high temperatures etc.

Plant roots transport a good deal of water and nutrients in/out of the
gravel also.
Regards,
Tom Barr

Tom,

You are a great resource. Thanks for your replies.

A question that struck me this morning. You mention you mix Flourite or Onyx
gravel with Peat. Wouldn't the humic acid from the peat mess up your CO2? How
do you measure CO2 in a planted tank with peat? Do you need to use a test kit
to measure CO2 (i.e., to measure CO2 more directly rather than inferring CO2
levels from carbonate hardness and PH) or does the humic acid not really
matter?

Also, is the study you referred to on substrate heating available on the
Tropica web site?

Thanks.

Bruce

Thanks Bruce,

Yesterday I disconnected the under tank heating pad. It is designed for that
purpose so I don't thing it should damage the tank. I did it mainly to lower the
water currents going thru substrate. I haven't got a chance yet to go to my LFS
but maybe in a day or to I will go buy some of those plant tabs... By the way
which ones are best?

--
Marvin
hlavac (at) rogers (dot) com


"BruceKGeist" wrote in message
...
My guess is Tom will be able to answer this better than I.

I do not think substrate heating is a bad thing unless you are having problems
keeping your tank at a good temperature. You have your tank at 86 degrees for
discus, right? I can't imagine you are having trouble keeping your tank below
this temp, but if you are, by all means shut off the heat.

There is one thing you should be cautious of. I am not sure how you are
heating the under side of the tank, but if there is enough of a temperature
build up you might crack glass. That could be a big bummer. I suppose you
have already considered this. Glass generally cannot tolerate too much of a
temperature gradient.

I seriously doubt that heating the substrate will cause too much plant tab
fertilizer to seep into the water column. If you want to be sure, you may
want
to monitor your iron, nitrate, potassium, and other critical nutrients to
determine if too much nutrient is seeping in the water column.

As for plants liking warm bottoms, well, they don't often get that in their
natural ecology. Therefore, I of reject that hypothesis. I think someone who
lives in Detroit (like me) in the winter was feeling cold one winter day, and
decided plants must like warm bottoms! The only reason I've heard that makes
any kind of sense regarding advantages of cable heater is as Tom suggested,
circulation of nutrients. If this is unnecessary, as I am beginning to
believe
it is, then why waste the money!

As an aside, I like the Seachem test kits for everything except for Potassium.
(Seachem does not make a Potassium test kit that I know of.) For Potassium
testing I use the Aquarium Pharmaceuticals kit. If your nutrients go out of
balance, then consider testing your setup without heating. You probably
already have all your test kits, but if not, that would be my recommendation.

-Bruce

(GregSki) wrote in message
Dupla traces daily (the recommended dosage). Ever since I read that Fe
levels of about 0.2ppm can cause thread algae I halved the traces as
well as the tablets. This hasn't done anything to the algae yet (in 2
weeks). I have been adding K+, NO3 and PO4 weekly but a little bit
above what you are suggesting. I was adding about 20-30ppm of K+,
15-30ppm of NO3 and 0.5ppm of PO4 (that's with no fish in the tank).
Hmmmm...might have to change my strategy then.


I really wish folks would not assume that 0.2ppm Fe residual is
somehow a good level.

It's not nor is maintaining a residual.
Nor is a single Iron test kit I've used worth a wooden nickle.
Folks test something that is very difficult to assume much about with
kits that are not telling you much.

The thing to "test" with traces or other nutrients is simply keep all
the nutrient levels relatively the same and manipulate one at a time
for at least a 3-4 week run to ascertain the effects on plant growth.

I grow plants, not algae. Therefore the focus should be on their
health, not the algae. Healthy happy growing plant is no match for
algae.

Folks seem to get bulldogged into thinking that iron or PO4 is the
cause of algae woes. Well, if the other stuff is off, it can help
algae but if the NO3, CO2 light etc are fine, you can add a large
amount of both and not get a lick of algae.

So do they cause algae? Not by themselves. It is those other
nutrients, K, lack of NO3 etc that are all out of balance.

If there is an algae inducing nutrient it is NH4.

Regards,
Tom Barr