This very compact heater with external digital temp controller. It heats up the jar/tank to whatever temp u need. It's easy to read if you tie strap the cord in the right place.

A small 2 gallon & is just what i needed to get the temperature up. I have a 10 gallon tank and as of 2 hours it has made it to 69 degrees. Since the water temp is only a few degrees warmer than my house temp, a 10w is plenty for such a small tank...  Read More

It is important to properly size the heater with your tank. It's fully submersible, so you don't have to worry about it being too big or bulky. Great adjustable mini heater.

The thermostat seems to be calibrated perfectly. The only thing i would say is that the thermometer part is very close to the cord so that's a bit of an uncomfortable placement to constantly check on my bettas status. Built in thermometer.

Highly dissatisfied. Also the suction cup occasionally pops off the wall of my tank.

The unit is off by as much as 5° f. Tried to bump it up to 83f, maybe make up the difference, but nope. Does not heat.

The fluval e-series is the best aquarium thermometer on the market. I have a 30 year old 44 gallon fresh tropical water pentagon shaped aquarium. In my 29 gallon high, the 200 watt works great.

Led back-lit lcd display is nice and makes checking the temp very handy. Microprocessor control makes setting the temp easy, as well. Lighted digital display in tank is a bit unsightly, but it is easy to read.

Took me a while to finally purchase this due to all the bad reviews. I'm sure many have had defective units but these heaters are wonderful when functioning properly. I've never had that issue, so i think it's more about aesthetics than anything else....  Read More

It never fluctuates. Turning it down to 75 is fine, but since it will reset to 77 automatically after being powered off (or a power outage), that's somewhat annoying.

No problems with lf (low flow) warnings on the display or wild heating or cooling. I have to buy and place a wavemaker close to the heater and problem solved.

I suspect this was simply a faulty unit as i have a fluval 306 filter. Temp reading is always off.