Best Inline Aquarium Heater

 This article reviews inline aquarium fish tank heaters in an attempt to help you choose the best one for your fresh-water or salt-water fish tank. Many factors need to be considered in order to do so. However,  There are already some famous brands out there, and all you need to do is to understand which one meets your needs the best.  
External heaters are usually made in 300 and 500 wattages and are suitable for large aquariums. Inline fish tank water heaters help you remove as much extra equipment attached to the tank as possible, but they are not submersible and should be connected to canister filters by an appropriate hose. It is important for the hose to fit the connection area so as to prevent leakage. Some other important factors are presented in the chart below to help you decide on the best external aquarium heater.
 

Hydor inline heater	A unique external heater for aquariums with the exclusive PTC (Positive Thermal Coefficient) technology. A possible downside to Hydor inline heaters is their lifespan which in some cases lasted less than a year.
Safety	Adjustability & Accuracy	Price
5	4	4
Digital indicator	Hose connection adaptively	Lifespan
x	4	3
Total Score (1-30) : 20

 

JBL inline heater	The integration in the filter circuit ensures a very even distribution of the water temperature with an accuracy of +/- 0.5 °C and a switching interval of 1.0 °C in the aquarium
Safety	Adjustability & Accuracy	Price
5	4	3
Digital indicator	Hose connection adaptively	Lifespan
5	5	4
Total Score (1-30) : 26

 

ISTA inline heater	Provides high accuracy by 2 temperature sensors designed to monitor the temperatures of water Inlet and outlet. Thermal spraying glass causes faster heating process.
Safety	Adjustability & Accuracy	Price
5	4	4
Digital indicator	Hose connection adaptively	Lifespan
5	5	4
Total Score (1-30) : 27

 

SUNSUN inline heater	SUNSUN, Akl, Datoo, and Feenng all have the same platform and chip, so they all get same ratings. Heater's temperature control system uses advanced STM8 chip, which ensures a precise and perfect temperature control within the range of 68 ℉ to 95 ℉ (20 °C to 35 °C). Most reported problem with these heaters is leakage in their hose connections.
Safety	Adjustability & Accuracy	Price
5	4	5
Digital indicator	Hose connection adaptively	Lifespan
5	4	3
Total Score (1-30) : 26

 

Conclusion:
In these comparison charts, ISTA inline heater receives the best rating, but JBL and SUNSUN are also good enough to be in watch list as second choices.