The Puffer Forum

Dear one and all,

What do you think of using a heat mat as a cheap alternative to under-gravel heating wire? The local pet shop stocks these in a range of sizes (12" - 80") and they cost much less than heating wire (£20 compared to £40). Logically speaking, I cant see any reason why this method wouldn't work; however, you cant beat the voice of experience.


Regards

Chris

N.B. The heat mat will serve to create convection currents in a planted aquarium.

NIMT

Substrate heating cables are a dead issue here in the USA as most folks have decent central heating systems. The dangers of "cold feet" are grossly exaggerated and the benefits of substrate convection have never been proven to be useful or significant. Those who made significant investments in cables have mostly (but not entirely - there are a few holdouts) tossed them out.

Thank you for your advice. Funnily enough, most homes are centrally heated here as well; although, I'm not sure how a uniformly heated room is going to have the same effect as an under-gravel heating system.

Anyway, if you say there is little or no evidence to warrant their use, then I may as well save my cash.

Kind regards

Chris

Despite what Dupla used to say (i don't know their current positions), substrates in the wild are rarely warmer than the water above them, and upwellings of water through the substrate are quite far from universal conditions in heavy plant growth areas. Aquatic plants are far more likely to have, and are very well adapted to, low O2 tension substrates. Diffusion and conduction are enough.

If you want substrate flow, try prefilterd RFUG. IME it works fine for plants. I don't think it is the best possible technique, but it certainly works.

I have actually used a terrarium-style undertank heater under a small (24" by 12" by 15" deep) tank. Worked perfectly well for many years. Used both for a marine tank and then later on in a freshwater tank. Plant growth was excellent. Also no problems with anoxic conditions over 5+ years of running (though as RTR says, a certain amount of anoxia in the substrate is actually very normal). No problems with over/underheating if you use a thermostatic controller as well. Much cheaper than heating cables.

Cheers,

Neale

I just got a small 4"x5" terranium heater for my 3liter nano planted tank this morning for a tenna. Im hoping it will work well enough!

I would mention that the heating mat needs to be big enough for the whole tank. At least, mine was 24" by 12", which was the size of the bottom of the aquarium. I have no idea if a mat big enough for just a corner of the tank would do the trick.

Cheers,

Neale

All sounds good. Interesting to hear that other peeps have experimented with heat mats. On the other point of substrate temperatures/O2: its worth pointing out that in the natural environment, substrates are constantly turned over by a multitude of invertebrates and, therefore, aid mixing. Water currents are also a consideration.

one thing would worry me , is that they arent water proof

Ouch, yeah.. splash a little water and zap!

mine's right under the tank with only the cable showing and the tank has a little rim round the bottom so theres no danger of that in my tank unless I spill major water

No problem, the mats are totally waterproof. They are made of plastic with thermal strips running through (approx 3/4 mm thick). They are designed to be placed underneath the base of the tank (hence mat!).

Make sure they can take the weight of a full tank of water on them...