Water return line below substrate?

[Vorian]

I read somewhere about warming the temp of substrate in a planted tank to create currents to keep from having dead zones among the plants in a heavy planted tank.

I figured it might be a good idea to use the return line ( which would have a ETH inline heater ) and snake it along the bottom of the tank to the furthest side from the intake line and have it release the warmed water at the bottom far side. this way the warmed water is constantly circulating.

Seems like it would be efficient to me, but I havent done it yet and wanted to know opinions.


Thanks,
James

[GrillMaster]

Warming the substrate wont alieviate dead spots. Water circulation will.

hth
Mark

[Vorian]

well, warm water rises thus cooler water would have to sink lower therefore creating a current. I guess that was the thinking behind it. by raising substrate temp and having a warm water outlet at the bottom of the tank it would create currents therefore removing dead spots and keeping the aquarium at a fairly stable temp in different water levels.

[GrillMaster]

I dont know where you are getting warm water creates current...Temp of the water, where ever it falls has nothing to do with current.

[White Worm]

In a closed environment like the aquarium, temp will most likely equalize. I dont think there would be a measurable difference or cold spots no matter where your return comes into the tank.

[Polar_Bear]

Actually the idea stems from the use of sub-soil heater cables and does work. In truth they are more trouble than they are worth and it is the main reason they have fallen out of favor (just try pulling an Amazon Sword one time and you'll know the reasons why). Unless you are planning on snaking the water line through the substrate it would be pretty pointless IMO, since you will not get the convection currents you are looking for. The only thing I can see it doing is slowing your water return rate due to a much longer return tube length.

[Vorian]

alright, theres some interesting answers and I see the points. I understand the aquarium being a smaller enviroment its easier to control, but they use a reverse system in a reservoir near me which uses the same concept but kinda backwards for the opposite purpose.....


well thanks for the answers, I see that its probably better an idea for larger environments.

James

[diablocanine]

Some have had great success using substrate heating in a planted tank. Keep in mind any return line you use will eventually need the mulm cleaned out.....DC

[Apistomaster]

Unless an aquarium is set up in a very cool environment I could never see what benefits one could gain from substrate heating. Using a probe type thermometer test the substrate and the water column and I think you will find there is no difference in the temperatures.

Diffusion not circulation assures transport of nutrients and wastes sufficient for good plant growth. If you have problems with substrates becoming anaerobic the problem is one of excessively fine grained substrates and/or inadequate routine maintenance.

Having kept planted aquariums for over 40 years I have yet to find a reason to worry about this. More concern should be paid to the type of substrate, fertilization and lighting.