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Best Overall: Aqueon Adjustable Pro Aquarium Heater
While there’s no shortage of specialized heaters, sometimes all you need is a great all-around product that gets the job done, does it well and won’t wreck your budget in the process. The Aqueon Pro Submersible 100W Heater is solid through and through, with durable, non-corrosive construction and even heat distribution. The heater has a range of 68 to 88° F and is accurate within one degree of the desired temperature. It’s fully submersible, can be used in fresh or saltwater tanks and automatically shuts off and resets in the event of overheating.
Customers say that the Aqueon Pro Submersible 100W Heater is visually unobtrusive and reliably keeps a level temperature in their tank. With its combination of a simple setup and quality construction (some buyers have gotten years out of it), it’s a great choice for newbies and experienced aquarists alike.
Best for Turtles: Tetra Fauna Aquatic Reptile Heater For Frogs, Newts & Turtles,100 Watt
As you’d expect, what works for fish doesn’t necessarily work for other, larger animals—like turtles. You’ll want a heater that’s sturdier than your average one and less likely to be jarred by movement, and the TetraFauna Aquatic Reptile Heater is a great option. Two oversized suction cups ensure it’ll stay in place even if it takes a full-on hit from one of your reptile friends, while a protective plastic cage keeps it safe from harm. The 100w heater is fully submersible and specifically designed for reptile aquariums, keeping your tank at an optimal 78° F.
According to customers, this heater is a “turtle favorite,” writing that it keeps the temperature exactly where it needs to be. The protective cover also ensures your turtles won’t accidentally burn themselves if they come into contact with it.
Best Electronic: Fluval E Electronic Heater
While countless heaters purport to keep your tank’s water at a steady temperature, you’ll often need to test it with a second thermometer to confirm your device is working properly. Not so with the Fluval E 100-Watt Electronic Heater, which has an LCD display that gives you an instant reading of your water temperature. The reader can be toggled between Fahrenheit and Celsius and relies on two sensors to provide a high level of accuracy. It will also change color to reflect a shift in temperature, but the heater should keep the tank within two degrees of what’s been selected. For larger tanks, the heater is also available in 200 and 300-watt models.
Customers say the Fluval E 100-Watt Electronic Heater is well designed, with a sleek profile that blends in with the tank, while the digital temperature reader is spot-on—and it couldn’t be easier to give it a quick check as you walk by.
Best Titanium: Finnex Hang-On Electronic Controller Aquarium Heater
For the serious aquarist, a titanium heater is designed for years of continuous use thanks to quality materials that are virtually indestructible. The Finnex Electronic Controller Aquarium Titanium Tube with Heater Guard is highly corrosion-resistant and will hold up for years in both fresh and saltwater tanks. Titanium also heats up more quickly than other materials, rapidly giving you precise temperature within two degrees of what’s been selected (the controller hangs outside the tank).
The Finnex heater comes in a range of models with varying levels of electrical power—from 50 watts on up to 500, depending on the size of your tank. Customers write that it has absolutely stellar build quality—letting them rest assured it will never crack like a typical glass tube or (gasp!) electrocute their fish.
Best In-Line Heater: ISTA External Heater Aquarium Heater
Want to save some space inside your tank and dedicate more room for fish and less for hardware? Consider an in-line heater, which warms up the water in your tank from the outside via an attachment to its filtration system. This one from ISTA is easy to install and highly efficient, thanks to its thermal glass design. Temperature can be set with the push of a button (an LCD shows the current temperature inside the tank), while sensors detect the warmth of the water flowing in and out for a high degree of accuracy. It’s available in six different models for various tank sizes and can be used with both fresh and saltwater tanks.
The ISTA in-line heater is incredibly consistent, customers write, and is truly a “set and forget” heater that won’t corrode or break over time. One note: The device’s LED only offers Celsius temperature readings, but a quick Google search should be an easy solution for U.S. customers. All told, it’s worth the slightly higher price tag to keep the heater outside the tank and leave more room for the seascape you’ve taken great care to maintain.