# Under tank heating or reverse under-gravel filtering?



## justissaayman (4 Aug 2013)

Would this be a good idea?

Please this heating pad under the tank ( Reptile Vivarium Propagator Heat Mat Moisture Proof IPX7 Triple Layered | eBay) and set it up on a timer along with a smaller internal heater.

This would create a convection current and keep the soil warmer. What you think?

*OR*

Do you guys think (as per this months PFK magazine) reverse under gravel filtering would be a good idea with an external? My thinking behind this is that all the flow will go through the substrate (in my case soil) and move upwards meaning it will spread nutrients and co2 throughout the water column, or would I be wrong in my thinking?


----------



## Christian Walker (4 Aug 2013)

Im no expert but I am pretty sure that reveres UG filtration is a no no for a planted aquarium.  Im sure I have read that on several occasions but someone else will clarify (or tell me Im wrong haha).  As far as heat cables and pads go, they are not really considered worthwhile anymore, although I remember briefly seeing a thread on here that one was used during a dry startup for a planted tank.  As far as I am concerned though, under gravel filtration has long since been obsolete.  Just my thoughts mind.


----------



## justissaayman (4 Aug 2013)

Thanks Christian. Just saw it and thought it had merit.

Reason im looking at heating pads is that I have been reading through my BOOK OF ADA and they have a substrate warmer which creates a convection current through the substrate and it seems like a logical idea.


----------



## Christian Walker (4 Aug 2013)

justissaayman said:


> Thanks Christian. Just saw it and thought it had merit.
> 
> Reason im looking at heating pads is that I have been reading through my BOOK OF ADA and they have a substrate warmer which creates a convection current through the substrate and it seems like a logical idea.


 
No worries.  Im not sure how old that book is, but sometimes even Amano changes his mind, LOL.  I think if you do a search on here for subtrate heaters, substrate heater cables, etc, that they are now generally poo poo'd although I can understand the theory and it does indeed seem logical.  I just think that if consensus seems to think they are not necessary I would not want to waste my money on it, but I also think there is probably no harm in using one either.


----------



## justissaayman (4 Aug 2013)

Its their new book, very informative but badly translated 

You see the problem with heating wires is that roots get tangled etc etc and that I can understand must be very irritating. With a pad which sits dry under the tank itself it would create just enough heat to get the bottom water to move through the substrate a little bit for a little bit of time during the day. I might try it or I might not... really wanna do the soil tank as 'green' as I can and a 40w heater extra wont be helping my electric bill.


----------



## Mike Edwardes (4 Aug 2013)

I've been wondering about this too. Last time I had a planted tank (in "The Optimum Aquarium" era) substrate heating was regarded as a "must have". Now it seems to have gone away. I wonder how many of these claims are actually based on evidence of effectiveness? 
Certainly, when I eventually get round to setting up my nano, which will be in a room that tends to get cold in winter, it will have a small, low wattage heatpad under it to boost the temperatures when needed, according to the season.


----------



## Tim Harrison (4 Aug 2013)

From what I've read heating pads don't make a difference either way, other than perhaps with regards personal choice. I think originally one of the reasons they were introduced was as a discrete alternative to visually intrusive internal heaterstats. However, since the introduction of inline heaters they've become something of an expensive white elephant.

I've grown plants in soil substrate very successfully using interlocking undergravel filter plates powered by large powerheads...not reverse flow though. The soil - a layer about 40mm thick - was sandwiched between 1mm grade plastic mesh, which held it firmly in place. It was well over 20 years ago and at the time - as probably now still - it was definitely regarded as a no no if you wanted to grow plants successfully.

I can only speculate why it worked so well...but I've an inkling the success was largely to do with vastly increased flow and distribution over pant roots perhaps similar to the way hydroponics works. After a while there were definitely a lot of fibrous roots penetrating the void below the soil. I'm not sure how much of the flow was actually through the soil itself though and how relevant that was, but either way it would have been minuscule compared to the flow pulled in from around the edges which were just gravel.

Incidentally, it was the only means of filtration in a very well stocked and extremely healthy tank, which ran for years with very few water changes and without any trouble whatsoever.

Also I think the under-soil flow and distribution of O2 would most likely have created another oxidised microzone in addition to the one at the soil surface. Just to put that in perspective, the oxidized microzone is the very thin highly aerobic surface layer of soil that interfaces with the water column. It is of huge importance in a soil substrate tank since it supports the hive of microbial activity needed to neutralise toxic substances and unlock nutrients.

I originally included this in my soil substrate tutorial and similar submission to PFK but removed it because it was too verbose to print. Reverse flow sounds interesting though...I've used that before as well but only in a marine tank and through coral sand. I'll have to purchase a copy of PFK and have a read.


----------



## justissaayman (4 Aug 2013)

Their using the reverse UG filter in a goldies tank but after reading all the stuff from ADA (see my note below) I can only think that having some flow through the substrate will be good and feeding the nutrient rich water from the bottom to the top and then back again might have some benefit as the root growers would have a constant flow of nutrient rich water with no still standing stuff and then that same water goes up to the plants like mosses, ferns and anubias'

Note: With all that said, ADA dont sell their heating plate as a heating plate for the tank but instead its PURELY there to heat the substrate and create that convection flow for that and that alone. The heating of the water still needs to be done by the heater itself. This tank isnt scheduled for another month and a half so Ill take my time and might even make a project out of it...


----------



## basil (4 Aug 2013)

I'll be watching Justis


----------



## foxfish (5 Aug 2013)

It is pretty obvious you don't need a inderpendantly heated substrate but if you want one that's fine.
Fads come and go - I have used the cable method and I still use mats for various applications.
Heat mats are great for emersed growing but in my mind their long term reliability is not very good....it's pretty difficult to replace a mat from under a full tank, cables are far more long lasting but you can see an ugly wire running down the inside of the tank.
I have tried injecting co2 through unravel plates, I still think this is a great way to get a very even distrabusion but my experiments have not proved conclusive as yet!
I can see a new fad coming........


----------



## justissaayman (5 Aug 2013)

Foxfish, your experience would be much appreciated in this.

Im actually thinking of just doing the reverse undergravel filtration as this would give me a more uniform flow of nutrients and co2 (will not be injecting or ferting at all). Would this work with the soil though?

I hadnt thought about failure of the matt so that is something to consider now... might get a inline heater along with the undergravel to extend the upward flow with convection.

Am I thinking along the right lines with this? Or do I really need the plants to move using a powerhead as well?


----------



## Tim Harrison (5 Aug 2013)

I doubt that either convection currents from an undergravel heating source or/and undergravel filtration will push or pull much, if any, water through the actual soil itself, hence the reason why heating mats don't appear to make much if any difference to plant growth. I'm sure that the actual flow direction is irrelevant since either way the principle will be exactly the same in a closed system.

Therefore, it would perhaps be better to just use normal flow, since there is always the risk that soil will be blown in to the water column. Reverse flow worked in a marine tank - for instance - since the idea was to push detritus out of the substrate and in to the water column where it would subsequently be sucked up by a canister filter thus keeping everything spic and span.

Normal flow worked for me because the flow was predominantly from around the edges and then under the soil through the 10mm void below interlocking plates, which were very similar to these Undergravel Tank Filter for Aquariums 23" x 12" UF-16P - All Pond Solutions.

Aquatic sediments are anaerobic by nature and macrophytes have evolved to grow in them. Nevertheless, so long as the soil is kept to a depth less than around 40mm it will not be too devoid of oxygen and your plants will find it relatively easy to uptake nutrients from it. I think that perhaps the best solution would be to just plant heavily from the outset - since macrophytes also release O2 and organic compounds through their roots - and let the oxidised microzone do the rest.


----------



## justissaayman (5 Aug 2013)

Thanks Troi. My first thought was to plant heavily from the onset and just run the JBL with the spraybar, but then this just got me thinking.

On a side note, can someone give me a link or a name of the stuff I can put over the soil which stops the sand topping from mixing with it? Plastic sheet type thing


----------



## Tim Harrison (5 Aug 2013)

This is what I use 5M Roll of Garden Greenhouse/Green House Shading/Screen: Amazon.co.uk: Garden & Outdoors


----------



## justissaayman (5 Aug 2013)

And thats holey right?


----------



## Tim Harrison (5 Aug 2013)

Yep, I think about 1 mm gauge.


----------



## justissaayman (5 Aug 2013)

Thanks Troi. Any chance you wanna sell me just a meter?


----------



## Tim Harrison (5 Aug 2013)

What with various projects an' all, I don't have very much left but you can buy it off the role here  Aquarium Gravel Tidy - Green - Price for 1.6 metres - New | eBay


----------



## justissaayman (5 Aug 2013)

Thanks Troi. Ill visit my local World of Water on the weekend and spy if they ahve


----------



## Christian Walker (5 Aug 2013)

Troi said:


> What with various projects an' all, I don't have very much left but you can buy it off the role here  Aquarium Gravel Tidy - Green - Price for 1.6 metres - New | eBay


 

Be careful with that roll though as its only 10" wide, so you would need double width for most tanks.  Probably the first link is a lot cheaper.  I think you can get it 1m wide sold by length at most nurseries though.


----------



## justissaayman (5 Aug 2013)

Thanks Christian, Ill see what my World of Water has then maybe go online if they cant help.


----------



## TallDragon (8 Jan 2015)

justissaayman said:


> Thanks Christian. Just saw it and thought it had merit.
> 
> Reason im looking at heating pads is that I have been reading through my BOOK OF ADA and they have a substrate warmer which creates a convection current through the substrate and it seems like a logical idea.



Dennerle eco-line Thermotronic Bodenfluter is what my friend recommended for substrate heat cables. For my cube tank he said I should get a corner filter, and heating cables which I should never turn off. I do not have space for an external filter. Worth looking into.


----------



## Edvet (8 Jan 2015)

I installed heatcables in my tank app 15 years ago. It has a  riversand mix in it. Originally i spread some clay/laterite on the bottom of the tank and covered that with the substrate app 5 cm thick. I did it to get some circulation in the substrate. The cables have been on since i installed them. Now and then a piece of it surfaces when dealing with the plants, i just push it back under the substrate. I never had problems with the substrate. Occasionally i will see some gas escaping bit it still seems healthy. How much of that has to do with the heating cable i can't say, but it has no detrimental effects i can discover. I do believe in a course riversand to be a very good substrate. It's been in there for 15 years and i never had to change it. Most detritus stays on top, but it's not so fine that it cloggs easy, doesn't damage cory's barbles and has nice natural colours, easy to plant in and doesn't influence waterparameters. Having trumpet snails helps too.


----------



## TallDragon (8 Jan 2015)

Edvet said:


> I installed heatcables in my tank app 15 years ago. It has a  riversand mix in it. Originally i spread some clay/laterite on the bottom of the tank and covered that with the substrate app 5 cm thick. I did it to get some circulation in the substrate. The cables have been on since i installed them. Now and then a piece of it surfaces when dealing with the plants, i just push it back under the substrate. I never had problems with the substrate. Occasionally i will see some gas escaping bit it still seems healthy. How much of that has to do with the heating cable i can't say, but it has no detrimental effects i can discover. I do believe in a course riversand to be a very good substrate. It's been in there for 15 years and i never had to change it. Most detritus stays on top, but it's not so fine that it cloggs easy, doesn't damage cory's barbles and has nice natural colours, easy to plant in and doesn't influence waterparameters. Having trumpet snails helps too.


Hi Edvet,
Thanks for the insights. May I have some questions:
- did you ever turn off the heating cables ?
- how do you fertilize the plants? (fertilizer balls?)
- what sort of filter are you using? is it low or high tech? Is it the 400 gallon tank that you are using the cables in or the 123 cube?

Does anyone else have thoughts about heating cables?


----------



## Edvet (8 Jan 2015)

This is after the first big rescape28738221_aquar0805052 by Edvet, on Flickr
You can see the double white cable on the right hand side behind the tank. I have kept it on for the whole time sicne i installed it. The first few years the plants could have utilized what was under the substrate, and i have only added some clay balls a few times. I did inject some EI Salts i dissolved with a needle under the substrate to see if it would make a difference, just not enough to be sientific about it. Basically i feed through the leaves.
The 400 is low tech now, but i did make it high tech for a while, see the journal.


----------

