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  • THEO Heater - 400W - Up to 105 gal.

THEO Heater - 400W - Up to 105 gal.

4 Reviews
Item: 205220

In Stock

Available: 1

Provide your tank with the proper temperature with the most advanced heating technology available. THEO heaters are designed with a peculiar cylindrical shape that renders them virtually shatterproof. Fully submersible, THEO heaters function with the PTC (Positive Thermal Coefficient) heating element, a special polymer sheet silk-screened with heating ink (like your car's windshield defroster), that enables them to run dry for a short time without damage. With an easy-to-read temperature dial, these heaters are the simplest, yet safest available.

400w model is rated for aquariums up to 105 gallons.

For complete product information, download the instruction manual.
Length15.5 in.
Width0.75 IN. DIAMETER
Max Wattage400
Warranty2 year
UL ListedYes
Internal Id
For complete product information, download the instruction manual.

Ratings & Reviews

4 reviews

  • 4 stars
  • 0 reviews
  • 3 stars
  • 0 reviews
  • 2 stars
  • 0 reviews

No complaints so far.


I have a 55 gal tank in a unheated basement. The ambient temperature swings from 60 to 70F. This heater holds temperature within a few degrees. This replaces 2x200W heaters which did not hold near as tight. The verdict may still be out as I only had the heater a couple weeks.

Customer Review


This is not the first HYDOR product I bought and just as the first, these heaters are crap. I have a 150 gal reef, 400watt is 100 more than heater it replaces and my temp swings from 73 degrees to 78. It cant even handle the room temp variations from when I go to work in the morning to evening. When room warms the tank warms too much.

Good heater


I have a 92 gal tank my room temp is 68, the heater keeps a constant temp of 78.
<br>So far I'm very happy with it.



These work so well, we had to turn them down but no complaints here.