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

🌊 Heat up your aquarium game with precision and safety!

SAFETY FIRST DESIGN - Built-in fish guard and automatic shut-off protect your aquatic ecosystem from overheating and harm.
SLEEK DURABLE BUILD - Compact black design blends seamlessly into any setup while standing up to daily use.
FAST EFFICIENT HEATING - 300W power ensures your aquarium reaches the perfect temperature swiftly, minimizing stress for your fish.
USER FRIENDLY LCD DISPLAY - Clear Fahrenheit and Celsius readouts let you monitor temps at a glance—no guesswork needed.
PRECISION TEMPERATURE CONTROL - Dual sensors deliver real-time, ultra-accurate water temps to keep your aquatic friends thriving.

The Fluval E Heater 300W is a high-performance aquarium heater featuring dual temperature sensors for precise monitoring, a clear LCD display in both Fahrenheit and Celsius, and fast heating technology. Designed with an integrated fish guard and automatic shut-off, it ensures maximum safety for fish and invertebrates. Compact and durable, it supports aquariums up to 375 liters, making it a reliable choice for professional and hobbyist aquarists alike.

Specifications

ASIN	B001VMSK0I
Best Sellers Rank	#27,195 in Pet Supplies ( See Top 100 in Pet Supplies ) #1,500 in Aquarium Accessories
Brand	Fluval
Brand Name	Fluval
Color	Black
Colour	Black
Customer Reviews	4.2 out of 5 stars 6,008 Reviews
Form Factor	Dish
Form factor	Dish
Fuel Type	Electric
Global Trade Identification Number	00015561107747
Heat Output	300 Watts
Heating Coverage	100 gallon
Heating Element	Radiant
Heating Method	Radiant
Included Components	Fluval Advance Electronic Aquarium Heater (300 Watt)
Indoor Outdoor Usage	Indoor
Indoor/outdoor use	Indoor
Item Dimensions D x W x H	4.6D x 8.4W x 46.2H centimeters
Item Type Name	HAGEN FLUVAL E 300W HEATER
Item Weight	0.37 Kilograms
Manufacturer	Fluval
Max Temperature Setting	2 Degrees Fahrenheit
Min Temperature Setting	20 Degrees Celsius
Model Number	A774
Mounting Type	Wall Mount
Part Number	A774
Power Source	Corded Electric
Power source	Corded Electric
Recommended Uses For Product	Indoor, Aquarium
Room Type	Bathroom
Special Features	Durable, Easy to use, Heating function
Special features	Durable, Easy to use, Heating function
UPC	015561107747 015561014168
Unit Count	1 Count
Voltage	230 Volts

Reviews

H**N

تم تجربة المنتج ودقيق بالحراره

دقيق المنتج قياس الحراره

16.02.2026

H**M

Amazing !!

The best heater I’ve ever bought for my 200 litters aquarium. Incredibly accurate! Well designed, and perfectly safe!

28.08.2022

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€ 107.16

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In stock

Sold byAmazon AustriaDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to Austria.

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