Best Aquarium Heaters For Large Tanks In 2020


Do you have a large saltwater aquarium? I guess the term “large” can mean different things for different people. Let’s just say for the purpose of this article that large is any tank size greater than 50 gallons. If you do have a large aquarium, then chances are you will need a heater or perhaps multiple heaters for it.

Now I’m not saying that small aquariums don’t require heaters, but larger tanks will need bigger heaters with higher wattage and generally cost more. So in this article, I will show you some of the best aquarium heaters for large tanks in 2020.

I mentioned in the Essential equipment guide for saltwater tanks, that aquarium heaters are considered a necessity. Unless you live in an area that is warm all the time, you may not need a heater. In fact, you might need a chiller to cool down the water temperature in the tank instead of raising it with a heater.

Choosing a heater for your saltwater tank is actually an important decision. Although they are not overly expensive, you want to ensure that the heater you buy is good quality and does its job of maintaining consistent water temperature. An aquarium heater that fails when you are not expecting it can be a disaster. Check out what happened to me when I experienced a heater failure on one of my tanks.

Benefits of having an aquarium heater


  • Maintain consistent water temperature – Consistency with all things in the saltwater aquarium hobby is the key to your success. Temperature is one of those things.
  • Having 2 heaters instead of 1 will give you the benefit of heating the aquarium water evenly. Also if one heater fails, you have a backup.

Types of heaters


There are a few different types of heaters you can use for your aquarium. They include hang on immersible heaters, inline filter heaters, and submersible heaters. The most commonly used heater in saltwater tanks is submersible, so I will only focus on them in this article.


How to choose a heater


There are a few factors to consider when choosing a heater.

  • What type of heater is it?
  • How much does it cost?
  • Will the heater be suitable for your tank? Size and power.
  • Reliability



If you are choosing a heater for a saltwater tank, chances are you will need it to be submersible. Whether you put it in your main display tank or install in the sump, a submersible heater will work for you. Of course, the cost will be a consideration. Aquarium heaters are for the most part very affordable and reliable.

But you should decide on your budget first as that will narrow down your choices. Also, ensure that the heater will fit in your tank or sump. Some heaters are very tall and simply will not fit. Choose the proper wattage of the heater to suit your tank size. A general rule is 5 watts per gallon of water.

There is no set hard rule for this, but just follow the manufacturer’s recommendations on heater size for your specific tanks water volume. Keep in mind if you have a larger tank, you may require multiple heaters.

A general rule of thumb for water volume and heater size:

  • 5-10 gallons – 25-75 watt
  • 15-30 gallons – 50-150 watt
  • 40-50 gallons – 100-300 watt
  • 55-75 gallons – 200-400 watt
  • 75+ gallons – 300-400 watt +


You also want to consider the reliability of the heater you are choosing. There are some main brands of heaters on the market that are known for their reliability. You can read the many reviews from people who have experience with the product, to help with your decision. After all, your saltwater tank will be the prized possession that you put a lot of effort and money into. Don’t make a poor decision and buy a cheap and unreliable heater that can cause huge problems for you.


How and where to install an aquarium heater


When installing your heater, you will have a few options. Some come with a bracket that you can use to hang on the back of your tank. Others will include suction cups to stick onto the glass. You can also install the heater in your sump, which is desired as it eliminates extra equipment in your display. Some heaters will also come with a guard that should be used to provide protection to your fish and inverts.

Marine Depot Aquarium Supplies

Aquarium heater maintenance


As mentioned above, a heater failure can be disastrous. I recommend you by a heater controller to prevent a heater malfunction from wiping out your tank. You should check the accuracy of your heater and make sure that it is holding constant water temperature on a daily basis.

You will notice with a saltwater tank, it is common for salt creep to build up on many things including the heater. It’s a good idea to unplug and remove the heater from your tank to rinse and clean it periodically. If you are using suction cups, check to make sure the cups are still holding over time. They are known to lose their suction not allowing the heater to stick to the glass. You can buy replacement cups online.


Check Out: 11 Best Aquarium Gadgets Under $50

Best aquarium heaters for large tanks


#1. Eheim 300w Heater


The Eheim brand of heaters is my #1 recommended choice. They are a trusted and reliable source for many aquarium products and their heaters are no exception.

Features and specs:

  • Shatterproof glass construction – made with laboratory-grade glass
  • Free of pollutants, resistant to chemical and biological substances
  • Temperature can be precisely adjusted from 65F to 93F
  • Control accuracy +/- 0.5C
  • Thermo Safety Control – automatic shut off when taken out of water
  • On/Off Indicator Light
  • Includes a mounting bracket and suction cups
  • Safe for in-tank or in-sump use
  • Long power cord 5.6 ft
  • Fully submersible
  • 19.6″ tall



The Eheim 300 Watt aquarium heater is available on Amazon.


Fluval E Series 300 Watt Heater

The Fluval E Series 300 watt heater is well built, reliable, and has some really great features. This included the built-in digital LCD screen. It is one of the most technologically advanced submersible aquarium heaters available on the market today.

Features and specs:

  • Dual temperature sensors provide accurate real-time water temperature
  • LCD screen shows both F and C – temperature ranges from 68F-93F
  • Includes heater guard
  • Up to 100-gallon tank size
  • Dimensions: 2 L x 1.125 W x 14 H”
  • Safety shut off
  • VueTech technology will show a different color screen if the temperature varies by 2 degrees
  • Easy to adjust the temperature in 0.5-degree increments
  • Includes heater bracket and suction cups
  • Fully submersible
  • Safe for in-tank or in-sump use
  • 5-year warranty




The Fluval E Series 300 watt aquarium heater is available on Amazon.


Cobalt Aquatics Neo-Therm 300 Watt heater

The Cobalt Aquatics Neo-Therm heaters consistently receive 5-star ratings from customers. They are very well built and reliable. A really nice feature of this heater is the modern slim design. It’s not round like most aquarium heaters. Perfect for a tight space in your tank or sump. It’s also built with a shatterproof design, so you won’t have to worry about it breaking in the tank.

Features and specs:

  • Dual heating elements
  • Slim modern design
  • Very accurate +/- 0.5 degrees
  • One-touch setting system
  • LED display shows actual tank temperature and set temperature
  • Temperature range of 66F-96F
  • Dimensions: 10 7/8″x 2 1/8″ x 4/5″
  • Thermal protection circuitry shuts down the heater and prevents overheating
  • 3-year warranty
  • Up to 80-gallon tank size
  • Fully submersible



The Cobalt Aquatics Neo-Therm 300 Watt aquarium heater is available at Marine Depot.


Other quality aquarium heaters that are worth considering:



Thanks for reading!