Just can't seem to adjust the temp. It flashes 77, but the temp stays at 75. Why?

I was having the same problem, though mine was stuck at 74.5--it stayed blue and never got higher, though it was set to 77. I called Hagen, and they said try unplugging it for 10 minutes, then plug it back in to see if that helps. It didn't; they'd said if that was the case it was defective and to return it. Mine was <1 week old.

I just bought this item September of last year and it wont let me adjust the temperature after the initial setting when I first had it

So you move the adjusting orange dial/thingy and doesn't change temp? Some times you have to move it all the way, let it return to the neutral position and the move it again to and so on. If that doesn't work, it may be faulty, contact Fluval, these have good warranty.

does this heater go in the tank

To clear any confusion, the heater is fully submersible to 39 inches. The photos in the instruction showing tank placement are misleading. The ones marked with an X means do not let it hang by the cord and do not just lay it on the bottom of the tank. Rest assured that the unit is sealed well and you are better off fully submerging the unit to prevent water evaporation from negatively affecting the heater.

Will I have "low flow" problems running only sponge filters?

Your air pump running the sponge filters circulate the water. The pump power will determine whether or not there is “low flow.”

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Q: I just bought this item September of last year and it wont let me adjust the temperature after the initial setting when I first had it

So you move the adjusting orange dial/thingy and doesn't change temp? Some times you have to move it all the way, let it return to the neutral position and the move it again to and so on. If that doesn't work, it may be faulty, contact Fluval, these have good warranty.

Q: does this heater go in the tank

To clear any confusion, the heater is fully submersible to 39 inches. The photos in the instruction showing tank placement are misleading. The ones marked with an X means do not let it hang by the cord and do not just lay it on the bottom of the tank. Rest assured that the unit is sealed well and you are better off fully submerging the unit to prevent water evaporation from negatively affecting the heater.

Q: Will I have "low flow" problems running only sponge filters?

Your air pump running the sponge filters circulate the water. The pump power will determine whether or not there is “low flow.”

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Description

🌊 Keep your tank thriving with precision and protection — because your fish deserve the best!

AQUARIUM GUARDIAN - Built-in fish guard protects your aquatic friends from harm, combining safety with performance.
TRUSTED DURABILITY - Backed by a 5-year warranty, this heater guarantees long-term peace of mind for your aquatic ecosystem.
SLEEK SPACE SAVVY - Slim mounting bracket fits seamlessly in any indoor aquarium setup without clutter.
SMART DUAL SENSOR TECH - Real-time monitoring with intelligent microprocessor ensures stable, reliable temperature control.
PRECISION HEATING MASTERY - Adjust temperature in ultra-fine 0.5°C increments for the perfect aquatic climate.

The FluvalE 300 Watt Electronic Heater delivers precise temperature control with 0.5°C increments, dual temperature sensors, and an intelligent microprocessor system. Designed for both freshwater and saltwater aquariums, it features an integrated fish guard for safety and a slim mounting bracket for a sleek indoor setup. Backed by a 5-year warranty, this 300W heater ensures reliable, efficient heating to maintain the optimal environment for your aquatic life.

Specifications

Brand	Fluval
Color	Blue
Form Factor	Aquarium Heater
Indoor/Outdoor Usage	Indoor
Product Dimensions	1.8"D x 3.3"W x 18.2"H
Recommended Uses For Product	For use in freshwater and saltwater aquariums
Mounting Type	Slim mounting bracket
Room Type	Living Room
Heating Coverage	100 square feet
Burner type	Radiant
Fuel Type	Electric
Voltage	230 Volts
Min Temperature Setting	20 Degrees Celsius
Max Temperature Setting	2 Degrees Fahrenheit
UPC	015561107747 015561014168
Global Trade Identification Number	00015561107747
Manufacturer	Rolf C. Hagen (USA) Corp.
Part Number	A774
Item Weight	13.1 ounces
Item model number	A774
Is Discontinued By Manufacturer	No
Size	E300
Style	E300
Material	Plastic
Pattern	Heater
Wattage	300 watts
Item Package Quantity	1
Type of Bulb	LED
Switch Style	Push Button
Usage	Indoor
Included Components	Fluval Advance Electronic Aquarium Heater (300 Watt)
Batteries Included?	No
Batteries Required?	No
Warranty Description	5 years; fluval e series heaters are guaranteed against defects in material or workmanship under normal aquarium usage and service for 5 years. We offer a 5 year guarantee on all nonreplaceable parts which means that the heater will be repaired or replaced at the manufacturer's discretion, free of charge, when the complete heater is returned with proof of purchase and postage paid. This warranty does not apply to any heater that has been subjected to misuse, negligence, or tampering. No liability is assumed with respect to loss or damage to livestock or personal property irrespective of the cause thereof.

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