Patented heating element automatically turns off if water level declines
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Easy temperature adjustment - knob clicks at every degree change
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Submersible heater with shatterproof glass resists breakage
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.
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.
Watts
Length
Aquarium Size (max. temperature increase of 8ºC)
50
7"
5-14 gallons
100
8.9"
14-26 gallons
200
12"
26-53 gallons
300
15-1/2"
53-80 gallons
400
15-1/2"
80-105 gallons
Safety Precautions
Unplug all electrical appliances before making water changes or performing any maintenance.
Use this heater indoors only.
Check voltage to verify the one that's reported on the heater label corresponds to your electrical supply.
Do no use if either the cable or the heater are damaged.
Do not plug in when out of the water.
Keep water at or above "Minimum Water Level" line.
Testimonial By:
Testimonial:
Robert C. Griffin III 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.
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.
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.
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 !!
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.
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.
A sharp drop in water temperature is extremely stressful to fish and can compromise their immune system. Improperly sized heaters may not be able to maintain their set temperature and cause aquarium temperature to fluctuate several degrees per day.
Temperature can be the single most important component in the life of your fish. Fish, in the wild and in our aquariums, are very sensitive to changes in temperature. Learn the affects of water temperature on fish health.
Don't take the quality of your tap water for granted. If you draw your water from a well, nature may not be providing you the perfect balance. If you are using tap water from your municipal department, it likely includes minerals and additives.
Algae are prolific and opportunistic organisms that take advantage of aquarium systems that are out of balance. Water quality issues create ideal conditions for algae. This article explains how proper water quality helps control algae.
Please note: Return of electrical equipment to Foster & Smith Aquatics for exchange or refund is limited to 60 days from the date of purchase. Beyond 60 days, please contact the manufacturer for repair or replacement as covered by the manufacturer's warranty.
6 am - Midnight, CST
 "Hydor Theo Heater")
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.
