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ISTA In-Line Heater Review

Tank Size Temp Display Longevity Price Rating
50 - 200 Gallons Celcius 2+ Years Medium 8/10

There are oddly few In-Line heaters on the market these days. They let us heat our tanks without taking up any water space and are exceptional at heat distribution. Combine them with a canister filter or return pump and you don't even need any special set up to use this kind of heater.

To be more specific on this in-line heater it serves its function fairly well. The ISTA does allow for more customization and the display shows us exactly what the temperature is set to. This can be more reassuring than a dial. It has several auto shut off safety features and two different temperature sensors to ensure the heater cannot cook the tank. It also has 3 codes that will flash on the display if the heater is having any issues. Overall this is a safe, reliable in-line aquarium heater.

A quick note. This heater does now come with the American style plug. It originally only worked with the 220-240 volt plugs, but they are now shipped with American plugs only.


Each code is fairly straight forward. When the numbers are flashing the tank is hotter than the setting. When HI is displayed the sensors are damages or the water temperature is over 36°C. LO means the sensors must have shorted out and the heater is no longer working. SE means that the two sensors are getting different readings. Unless the heater has short circuited you usually just need to cool the tank off. This is done with chillers, which are essential in hotter areas.


Setting up this heater means attaching it to whatever tubing you have. This can be a return pump, canister filter or refugium. As long as water is constantly moving through the heater to the tank it does its job. The best place to put the heater is the return tube of a canister filter. This will make sure the heater cannot get clogged, as the filter will have just removed any larger debris from the water before passing it through the heater.

For the ISTA you will need to use the included adapters and tubing to connect the heater to your own tubes. The adapters have nuts that you can tighten onto the tubes, which will make a strong and secure connection.

Note: The measurements for the hose are the inner diameters.


This heater works a bit differently than most when it comes to adjustments. Instead of typing in a number or turning a dial there is simply one button that says set. When you press it the temperature increases by 1° per press. The temperature rang is 20-35°C, or 68-95°F.Once you hit the max temperature the heater will lop back to the lowest temperature. So if you want to change from 30°C to 29°C you will need to press the set button 15 times. Going from 29°C to 30°C will only take one press.

The bottom number will show the temperature you have the heater set to while the top number shows what the current temperature is. The green light in the top left shows that the heater is on and should be on all the time. The red light will only turn on when the heater is actively heating the water.


There is a one year manufacturer warranty. They will usually make you pay the return postage, but it is a lot less than the cost of an inline heater. Not much else to say here.

Overall this is a nice in-line aquarium heater. It comes with everything needed to set it up and has a lot of fail safes to keep the tank from cooking. The only downside is that I have no idea how long it lasts, unlike the more well known Hydor, which is in my opinion the best inline aquarium heater.