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Hydor THEO Heater 200 Watt

Hydor THEO Heater 200 Watt


Item #: HD11302

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The THEO heater has all the essential features for maintaining your aquarium`s water temperature precisely and consistently. Featuring patented thermal technology (PTC) which makes it among the safest aquarium heater lines on the market and is UL Listed by design, not by the use of accessories.

Made from specially engineered shatterproof glass which, while not unbreakable, is designed to resist breakage in most normal aquarium situations. Highly accurate due to the use of precise micro-switch technology.

The exclusive technology used and the high quality of the components guarantee a long life.

  • For use in freshwater and marine aquariums
  • Submersible
  • Anti-thermal shock
  • Shock resistance
  • Graduated scale dial
  • Vertical or horizontal positioning
  • Maintains set temperature precisely
Model Wattage Length Aquarium Rating
THEO 200 200 Watts 12" 25-55 Gallons
THEO 300 300 Watts 15.5" 55-80 Gallons
THEO 400 400 Watts 15.5" 80-105 Gallons

Manufacturer information

Hydor has been producing a comprehensive range of equipment for aquariums and ponds since 1984 and offers the best in high-technology for the creation of a living ecosystem at home. The factory has developed thanks to the engineering competence of its founder and its continuous growth is based on the investment it has made in research and the development of innovative technical appliances. A competitive and dynamic structure of more than 150 employees regularly engages in the implementation of products which meet the demands of 50 nations and keep pace with the evolution of the world markets. The global quality is not a simple working method but a daily expression of mind.

4 Stars


Reviewed on
January 09, 2021

No, I would not recommend this.

It exploded !!!

The heater just exploded inside my sump. It gives out horrible smell. It has been in my tank for less than a year. I got an electrical shock when I tried to move an anemone out of the tank, not knowing what happen. All of my coral closed up and looks really stress out. Hope it will survive the ordeal!!!

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Reviewed on
December 09, 2019

No, I would not recommend this.

Hydor killed my reef tank - 100W - this model - Thanks Hydor

Cons: Severe Malfunction!

Within 1 day, I woke up and found my corals curled up and noticed the tank was 95 degrees. This 100w Hydor version cooked my corals, LPS, SPS thus causing bleaching, then death. The heater was 9 months old. When I pulled it out, it was still smoking! Do Not Buy These! Who would want a replacement when they aren't going to replace the corals.

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Reviewed on
March 25, 2019

Yes, I would recommend this.

Good and reliable

Pros: Reliable cheap heat for over a year now

Cons: May run a bit hot so had to back up with an inkbird for redundancy

I’ve had for a year now with no issues.This is installed on a nano 29 gallon and keeps temps stable but I do have it backed up with an inkbird to make sure.

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Reviewed on
August 08, 2018

Yes, I would recommend this.

Great Heater

Pros: Accurate, budget friendly

Cons: none

Using it currently on a budget reef tank and it works really well. great for the price. Temps are accurate

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Reviewed on
February 08, 2018

Yes, I would recommend this.

Excellent Product

Pros: Easy to use just plug in set temp and drop in sump

Cons: watch your temperature they are actually higher than the stamped settings

Love Hydor products, been running a saltwater aquarium for about three years now and have no mechanical failures with any of there products.

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Reviewed on
May 15, 2017

Yes, I would recommend this.

Performs very well

Pros: Price,colored dial for easy viewing

Cons: None

Very accurate temp reading,red dial for easy viewing.

Was this review helpful? 2 0

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