heating the roots of plants?

[red devil]

I saw an ad for a substrate heater. The ad said that if the roots of the plant are a little warmer than the water above the plant will be healthier, etc etc. I thought this was strange...I am not a chemist or physicist but I do understand convection. It seems to be that if you set the substrate heater for 1 degree warmer than the water above, the ss heater will be on continually, or until the water is the same temp as the substrate. Is this correct?

[180gz71]

Thats basically how they work. Although, not necessary. Ive only used one once, and there was no noticeable diffference.

[DarkSoul]

I would imagine that feeding oxygen to to the roots would have better results.

It does with potted plants anyway.

trust me, bury an airstone in the dirt at the bottom of a potted plant, and watch it grow better.

healthier roots too.


Cant speak for aquatic plants however.

[TKOS]

Or just get some Malaysian Trumpet Snails. They dig around in the dirt and help to oxygenate the roots. Nice addition to any tank.

[Rex Grigg]

Did the same add mention a high tech lubricant for legless reptiles?

There have been NO studies done that show substrate heater have any benefit. People that have them will make all sorts of claims. But hey I can make claims too. Doesn't prove squat.

If you have money to burn and love gadgets then by all means buy a substrate heater. But otherwise just have a good laugh.

[red devil]

Thanks! It is useful information...but the brunt of my question - put another way, is that it seems that if you put the heater under the gravel (or whatever) it is going to heat the whole tank up to the same temperature, so there will be no difference between the root area and above the root area, again because of convection. Is that correct?

[brads]

Thanks! It is useful information...but the brunt of my question - put another way, is that it seems that if you put the heater under the gravel (or whatever) it is going to heat the whole tank up to the same temperature, so there will be no difference between the root area and above the root area, again because of convection. Is that correct?

Correct. The entire tank will eventually become the temperature of whatever you set the substrate heater at so... Smart guy, you picked that right up. :)

[Star_Rider]

that may inpart be relative to the depth of the soil..soil is an excellent insulator..the water would cool the soil above the heater cool the soil below..heat exchange from the tank may cool faster than the heater can heat..a lot of parameters where there isn't much info.
and at what point is it too much heat??(random passing thoughts)

but I would suspect the heater may run all the time..
'does this heater have an adjustment?

[wesknox]

Red:

I've often wanted to experiment with this idea in the past. Over the years I've discovered a few things about substrate that has put me off of the idea.

* The more organic (fish waste) material that is in my gravel, the better the plants do and the worse the algae does.
* The less disturbance I do to the gravel, the less problems I have with algae

The convection of an undergravel heater is going to cause nutrients that settle into the substrate to leach back into the water column more than without the undergravel heater. My personal observations and things that I've read indicate that this is potential problems relative to algae growth.

I've not vacuumed a tank for more than 6 years and have not had to. I don't have a layer of detritus on the gravel nor a carpet of algae there either. Prior to this I did experiment with vacuuming and discovered I would get algae in significant amounts within a couple of days after vacuuming.

Some of my most wild plant tanks have been where there were so many plants that you couldn't get a vacuum in "edgewise" so to speak. One tank was 100g stuffed with Hygrophilia sp, and the other was was 100g with Crypts that were wall-to-wall and grew to within 6" of the surface (this tank had a ball of java moss in the middle that filled a 5gal plastic bucket when I took it to the LFS.

Bottom line is that I don't see the advantage of additional heat (or O2 for that matter) in the substrate vs the potential problems it can cause with algae. Most natural environments don't have heat source in substrate and they seem to do pretty well.

My two cents.

[Que]

Have you ever felt your heater in the tank? It feels warmer than the surrounding water. I would think the same for an undergravel heater. I think the gravel would be warmer than the water but probably not by much.

Q

[musho3210]

the hot water on the substrate will rise since that is basic science which means the cooler water then falls into the gravel, that cool water is oxygenated and rich in DOC and other stuff the plants love, the roots then absorb these nutrients in the new water, by the time the plants have finished sucking in the nutrients from that new water, the new water gets hotter and rises and cooler, more nutritious water goes back to the gravel. Thats how these things work. I wouldnt use these things to keep the whole tank heated....

[Mgamer20o0]

how it works and if it does any good are two different things.

[plantbrain]

Organic carbon can be bad as well as good, what counts is how much and is it maintained, heating cables can do neither.

Just like a drug, too much kills the patient, too little has no effect.

http://links.jstor.org/sici?sici=0012-9658(198610)67%3A5%3C1328%3ASMOGLI%3E2.0.CO%3B2-P

As you can see, Dupla and the various proponents of heating cables are quite clueless as they do not address such complex mechanisms (not hard to understand, rather a lot more to it than their marketing depts might suggest), nor have ever shown a single study to support even an iota of even correlative evidence, let alone cause.

If someone makes some claims, does not bother to delve into the real issues surrounding the topic, it really shows they have not done their homework.
Show me/us/anyone a study for support.

I've done far more homework than any of these companies have concerning sediments, flow rates and growth of aquatic macrophytes. I know I have because I've talked to these folks.

If they or others feel otherwise, they are more than welcomed to discuss the various experiments they have done that address such things as accumulation(the cables will increase the rates of organic matter, not dissipate it, fine at the start, bad later), flow rates, I've yet to hear a single study from a single proponent as to what a rate of optimality is for a single plant species, I've yet to here or see any studies or examples of growth rate differences between a non cable and heat cable treatment.

I have several studies that show even without the roots, (they cut them off), 4 species of submersed plants had the exact same relative growth rates when grown under non limiting conditions in the water column. This was done both in the field and in a lab aquarium set up.

When addressing sediments, you must address the water column at the same time. Otherwise the assessments are not fair and may confound your conclusions and data a great deal.

I really think given the observations folks have had, (a few folks will always think they saw better growth, same deal with adding sugar pills-placebo effects), the burden of proof is upon those that make the claim, those that are passionate about showing that it does work, those that sell them.

When I question folks about this, many suggest I'm a bad guy, being too hard etc. After 10 years of using them, at least that much testing, good professional background on this specific topic, several 1000$ spent on the infernal gadgets, I think I can speak fairly and definitely.

You do not need to be a professional etc, you do not need that many years of testing, but you'd better had addressed the issues, and shown definitely that they do work, because no one has done so yet to date.

One tank, "I think it does better" etc is not going to do it.
You need (a lot) more support than that.
You need a test, details and show it works that way you claim.
Other folks need to be able to verify and repeat it as well.
Other folks have verified what I claim, many times for decades now.

How much organic matter is good?
How much is bad?
I addressed those issues and provided some research support from Barko.

Cables supporters never once have ever offered a single references since 1989 when I first questioned their usage.

Math...........2007-1989= 18 years I've been waiting.
None of my own test ever showed any correlation or cause.
I've had far stronger affects on growth and health from merely changing the surface flow on the top of my tank, or doing a few more water changes, or cleaning the gravel once in awhile, watching the CO2 bit more, adding PO4, adding K+, being more consistent with my routines etc etc

Regards,
Tom Barr