PDA

View Full Version : Undergravel Heater Cables



Zoom
29-03-2011, 10:16
I recently purchased an aquarium book on planted aquariums, and decided that instead of skipping to the plants, I would read through the basics of setting up a planted tank, and came across an interesting chapter in the book where it discusses using heating cables under the gravel.

Basically it's a cable that is stuck to the glass base with the use of suckers. The cable heats up through resistance.

What the book goes on to explain is that whilst the plants absorb nutrients through the leaves, it is also imperative that it absorbs nutrients through the roots as well, as some plants can only take up certain nutrients through the roots. The problem comes in that we have very little, if any, movement or circulation of water through the soil base. Bringing in new nutrients through the use of water movement is therefore essential to the nutrient absorption. It also claims that in nature, the soil is naturally warmer than the water surrounding the plants, and that plants will often do better with a warmer substrate.

The heater cable works on the principle that it heats the surrounding substrate slightly higher than the water column, and this creates small currents between the cool water above the substrate and the heated water within the substrate.

The other benefit of this is that waste build up on top of the substrate (from plant matter, fish waste, and excess food) is also drawn into the substrate, and necessary bacteria that are within the substrate break this down better than if it were left on the surface of the substrate. It goes on to explain that area's immediately around the plant's roots will be high in oxygen, due to the plant bringing oxygen down through the root structure, and where there is not plants, anaerobic bacteria colonize the substrate. I'm not going to go into too much detail on the anaerobic bacteria, but basically it's often an area of a tank that is overlooked, (and sometimes seen as bad), but the benefits are huge. This slow movement of the water will provide the anaerobic bacteria with the necessary nutrition, but without "flooding" them with oxygenated water.

What are your guys thoughts and opinions on this?

(Dirk Bellstedt Laure Rudi wearsbunnyslippers ?)

shihr
29-03-2011, 11:11
some guys on APSA seem not to like this idea.. read this up a while ago..mixed emotions

http://www.apsa.co.za/board/index.php?topic=3384.0 - under gravel heaters

http://www.apsa.co.za/board/index.php?topic=415.30 - substrate (towards botom they talk about UG heaters)

f-fish
29-03-2011, 16:31
Zoom - I have looked at them before - most are powered by < 25 volts so low voltage - but I have not seen any with a thermostat - so I would assume it is always on. It also seems like this is not a replacement for your regular heater. I get the principle and it makes sense - but I just do not know if I want to commit more power to a tank.

But by the number of product available it does seem like it is a big thing in Europe - not cheap starting at 10m (100W) = R1500 depending on brand and quality.

Later F

Zoom
30-03-2011, 08:16
According to Tom Barr... it's not worth it. He did tests on it for 10 years and claims he didn't find any substantial improvement.

Rudi
31-03-2011, 19:38
Zoom,
I visit a few European forums and the use of heater cables seems to be something of the past.Very few hobbyists use them these days.
I think the benefits or lack of, is a matter of opinion.Some people swear by it,some says it's a sales gimmick.
I wouldn't waste money on it.Just my opinion.

Laure
07-04-2011, 08:07
Hi Zoom

I have also read a bit about their use and there is no clear proof that they provide any measurable improvements. Planted tanks can be complicated or simple...your choice.

SalmonAfrica
07-04-2011, 09:18
They come in handy with bigger fish - such fish tend to bash around our glass heaters and that can end up problematic. Of course, there are other ways around this (heater guards or using the heater in the sump), but I have seen a few people using undergravel heater cables as a solution to this.

Zoom
07-04-2011, 09:46
They come in handy with bigger fish - such fish tend to bash around our glass heaters and that can end up problematic. Of course, there are other ways around this (heater guards or using the heater in the sump), but I have seen a few people using undergravel heater cables as a solution to this.

Not too sure how this would eliminate the need for a normal heater. The undergravel heaters only raise the temp of the substrate by a degree or 2 more than the surrounding water. It's really just a warmer, and not a tank heater per se.

SalmonAfrica
07-04-2011, 10:01
Not talking from personal experience here, bear in mind. Whatever the case, it seemed to work for a few people.

Sean J
07-04-2011, 16:07
Hello guys! Long time...

These are my thoughts on this idea:

Firstly, in nature the water temp and the ground temp are 2 different things. Especially when the colder water is coming down a mountain into warmer areas. The water temp is probably around 10 degrees cooler than the ground temp. The further down it goes, the warmer the water gets. The warmer soil naturally radiates heat upwards into the water, thus warming it. Also, the evaporation that's happening on the surface of the water will add to the cooling effect of the water. Maybe not much, but it will still have some effect.

In a tank, the water temp and the soil temp are the same. The warm gravel is still the same temp as the water. Trying to make the gravel, or at least the water in the gravel, a different temp would only serve to actually heat your tank even more. And because the mats have no Thermostat, it would just continue to to draw power and use up unnecessary electricity. The idea of making water movement in the substrate isn't going to have a major influence, in my opinion. Also, what temp do these mats get up to? If it's roughly the same as the water temp, then there's no point. But if it's higher, then you're going to start heating the tank.