Heating 180 gal tank with coils/cords?

[tropterrarium]

I'm fiddling with my new 180 gal (36"Lx20"Wx60"H) warm terrarium. I first thought I heat it with an immersion water heater connected to the water feature and blowing air over the warm water. This raises the humidity too much.

So I've been thinking of using heating coil/cord, place it by the intake of a fan (hidden in card board tunnel) and let the fan blow warm air around the terrarium. The heating coil will be turned on/off with a thermostat (HerpKeeper system).

How much wattage will I need to raise the temperature 5-10F above ambient? Standard wattages are 12, 15 and 25 watts, which seems a bit low for my application. How hot are those coils getting?

I've also been thinking of using an immersion water heater with regulated high temperature (such as the Rena or Cobalt Aquatics Neo-Therm), and placing that next to a fan. Those come in higher wattages (to about 200 W, which may be a bit too much.). Heat capacity of air is much lower, but by blowing air over it, it may do the trick. Has anyone tried that? Will certainly void any warranty, but may be worth a 50-bucks experiment.

[keithrs]

I use my lights(4- T12)to warm my grow tent. The lowest day temp I've seen is 75 with the night temps falling down 60 or so.

If you need more then that... then you can heat water with a aquarium heater and circulate it through a small radiator/cooler. Mount it in front of one of your fans.

CPU radiator kit

[tropterrarium]

Hi Keith,

I have a 6x36"T5 fixture on top (dimmable ATI), but because the tank is 5' tall (60") there is much less heat input that on my 24" deep x 63" wide tank. So heat input from the t5s for the new tank is minimal. Sounds like your fixture is IN the enclosure, mine is outside. My tank temperature is about 2F higher than ambient.

The cooler idea is interesting. I wonder, though, whether I can just make a simpler installation with a water heater mounted behind a fan, so make it air-cooled rather than water cooled.

[keithrs]

Yes, my lights are in the enclosure.

Water has much more thermal mass than air. So if you heat the water than dissipate that heat from the water, you'll have a much more efficient setup. The surface area of an aqua heater is not very much compared to a radiator. That said, Your idea could work.

[tropterrarium]

Did a little experiment with a 50W Rena water heater I had lying around, placed so that the fan blows air through the opening of the heater. Heater holds up, and the tank is about 4F warmer than before. Have ordered now a 75W Cobalt heater, higher power, and larger surface area than the Rena, so should work better. Will follow up later

[keithrs]

Its git'n hot in here!!! LOL