Hydor Theo Heater

Patented heating film and special shatterproof glass make this submersible heater virtually unbreakable. Theo switches itself off if the heater is not fully submersed - avoiding overheating and damage. Precise temperature knob clicks in 1°F increments, and an indicator lamp lets you know when it's on. Suction-cup clamps included. 5-1/2 ft. cord. UL-Listed.

Please click on "More Information" for features.

• Adjustment knob
• Graduated scale
• Setting indicator
• Minimum water level line
• Indicator lamp
• Shatterproof glass

Patented Heating Technology
This submersible heater operates with PTC, a heating technology patented by Hydor. Its heating element is made of a special polymer that has been silk printed with special ink. The ink heats up with the passing of electric current, and the heat is transferred to the water. Its unique feature is that it is self-regulating. The heating element turns off automatically when the heater is not fully submersed in water (such as when performing water changes). This prevents overheating and breakage of the unit.

Safety Precautions

1. Unplug all electrical appliances before making water changes or performing any maintenance.
2. Use this heater indoors only.
3. Check voltage to verify the one that's reported on the heater label corresponds to your electrical supply.
4. Do no use if either the cable or the heater are damaged.
5. Do not plug in when out of the water.
6. Keep water at or above "Minimum Water Level" line.

Robert C. G
Arundel, ME

I bought the 25-watt version of this heater because it is one of the few that may be oriented vertically in the Eclipse System 3 aquarium. I couldn't be happier with my choice. The build quality is excellent and the heater consistently maintains aquarium temperature within a one-degree range.

Michael
Chicago, IL

My only problem with this heater is the dial. It does not label all of the temperatures. Otherwise it is "da bomb" in the heater theatre.

Eileen H
San Diego, CA

I love this product. I bought one and bought two more for my other tanks. It is very accurate and has a safety feature that I liked. Great product and a very good price from DrsFosterSmith.

G. M
Kansas City, KS

Great heaters. I own three ranging from small to large and I never have a problem with any of them. They seem to be accurate within 1 degree. I won't put anything else in my tanks.

Lori A
Palm Harbor, FL

I have purchased this heater for my red devil cichlid whom, are known to bite and play with tank plants e.t.c.. no problems here !!! Would recommend this heater !!

Daniel D
Oneill, NE

Love being able to control the temp with the dial. Way better than the plug-n-play heaters I've used in the past. It's nice being able to turn up the heat a little instead of dealing with the standard. Makes it way easier if you are breeding to set the 'mood' when you have control.

Josh M
Rochell, IL

I bought a 300 watt one for my 75 gallon tank and it keeps the temp right at 80 where I want it. Never have had any problems with the temp changing like the old heater I had did.

L W
New York, NY

For my air conditioned office, I have a 50 watt Hydor Theo Heater I use in my 2 gallon glass bowl for my Betta. I keep it at 71 and the water temps are 76. I had it for one week and it's working great so far.