Fluval T300 Fully Electronic Heater for Freshwater Aquariums up to 80 Gal.

I have been using this for 14 months with no issues it holds a good temp. What is more impressive is the Saftey off…. I drained the tank today while distracted and forgot to unplug the heater… I thought it was toast, but to my surprise it is functioning fine and it holding at perfect temperature after re filling the tank. That feature alone would warrant a repurchase if I am in need of another.

Best heater I’ve owned. It’s very accurate, I like the indicator- makes it easy for me to tell it’s working

I’m a believer in mild overkill when it comes to heaters because I like to keep my house cold. I got the 300 watt heater for a 55 gallon tank. In 3 hours it safely took my (new, uninhabited) tank from 67 to 78 degrees. I like the (mostly) black design that blends into my painted black tank background and the aesthetically pleasing light ring that displays whether it is currently heating or not. The adjustment dial seems to have a lot of little notches if not a continuous spectrum of temps to choose from. One minor annoyance was that when I pulled the product out of the box, the black heater guard that goes on the end was stuck in a bit of styrofoam way down in the bottom of the box. I almost threw the box away and assumed I’d just gotten one without all the pieces. Then when I applied it to the already-wet heater, it popped off a couple of times. It’s not strictly necessary for my needs since my heater is safely tucked away in a vertical position where fish can’t get to it, but still, watch out for that.

Purchased in Oct 2022, unit failed 18 months later in Apr 2024. With a 1 year warantee, it's not worth buying. Hagen did not recognize my 1 year extension of this warantee, and so it went into the trash. Ken

So far so good, I feel safe knowing my heater comes from a trusted company. Unlike, other Youtube personalities that claim to be a Co-Op. Can't trust them, I wouldn't want their fire hazard in my tank.Thank you Fulval for making quality products.

Nothing negative to say. It is a really well designed unit and pretty much disappears in my aquarium. Was easy to adjust temperature as well as the indicating light is way better knowing it is working properly even when it isnt actually heating. My future aquariums will have this series heaters from now on.

After researching aquarium heaters I learned about the new T series line by Fluval. I have the T 100 on the 20 gallon and the T 300 on the 75 gallon. The indicator lights blue for standby and red for active. The room is around 70 degrees but the heaters remain in standby for quite a while. When they turn on it it only for less than a minute. I have the heaters vertical and suctioned to the glass near the filter to get good circulation.

I like the fluval line. Have a 307 on a 75 gallon tank. The heater is under water. It keeps temperature from 79.1 to 79.7 for a month, so far.

Parecía ser un excelente termostato con la Li de encendido y en reposo, sin embargo disfunciono y ya no calienta. Lo tuve por menos de 1 año

I got the T150 for a 33 gal tank. The red and blue light indicator work perfectly as I have a hidden filter from Fluval 123 set up. So I can still the see through the tank cover since it is already hidden. The temp remains accurate with the dial adjustment. Highly recommended.

We have a 55 gallon and love the light the turns red when unit is heating or blue when temp is good.

Fluval products have been my go to so far. A bit on the expensive side when compared to other available products but they work so well for the price. Of course, fluval as a brand has been very approachable in responding to any queries.

I put this in my 55gal and it's kept a perfect steady temperature. Been running a month with no issues.