If the Fluval E Series Electronic Aquarium Heater is showing or flashing a blue light, then it indicates that there is a problem with the device. To see how you can potentially fix this issue, you can take a look at this troubleshooting guide from Aquarium Blueprints.
This article is based on the following versions from the E Series:
- Fluval E50 Advanced Electronic Aquarium Heater
- Fluval E100 Advanced Electronic Aquarium Heater
- Fluval E200 Advanced Electronic Aquarium Heater
- Fluval E300 Advanced Electronic Aquarium Heater
What does the Fluval E Series Heater blue light indicate?
If the LCD screen of your Fluval E50, E100, E200 or E300 is showing a blue light, then it means that the tank water temperature is currently more than 1 °C or 2 °F below the set temperature of your heater.
What does the E Series Heater flashing blue light indicate?
If the LCD screen is flashing a blue light, then it means that the current water temperature has fallen to more than 3 °C or 5 °F below the set temperature of the heater.
How to fix the blue light issue with the Fluval E Series
In order to make the blue light go away, you can try the following:
1. It is important to note that you are supposed to let your heater adjust to the water temperature of your aquarium before you plug in the device to a power outlet. Otherwise, the E Series may not be able to correctly measure the temperature of your fish tank.
If this is the first time you put the heater into your tank, or you took it out of the tank and then put it back in, then you need to wait at least 20 minutes before plugging the heater into the power outlet.
If you took the heater out of the water while it is still plugged into the power outlet, then you need unplug in as soon as possible. Afterwards, you need to let the heater cool down in the air for at least 60 minutes before you can put it back into your tank again. You should then wait at least 20 minutes with the heater in the water before you plug it back into the power outlet.
2. The E Series is designed to heat up your tank water by 6°C or 10°F above your ambient room temperature.
In other words, if your room temperature is too cool, then the heater can only increase the temperature of your fish tank to up to 6°C or 10°F.
To increase the temperature of your room, you can use a space heater and/or add insulation. You can also cover the top of your fish tank to give it better insulation. If possible, we also recommend moving your aquarium to a space that isn’t breezy as the wind will cool down your tank.
3. You should make sure that the water line in your aquarium reaches the minimum water level of your E50, E100, E200 or E300. If you let your tank water level fall below line labeled on your heater, then the device won’t be able to accurately detect the temperature in your aquarium.
4. Keep in mind that the blue light on the LCD screen may still show or blink a blue light even if you managed to increase the temperature into the desired range in your tank.
To make these error indicators go away, you need to unplug the heater, let it cool down in your aquarium for at least 20 minutes, and then plug it back in again. If your tank water is warm enough, then you should see the LCD screen display a green light.