Aqueon Pro 300 Submersible Aquarium Fish Tank Heater, 300 Watts, For Up To 100 Gallon Fish Tanks

We have a betta in an 5 gallon tank and I cannot say enough good things about this heater. We went through multiple "fixed temperature" heaters and they all proved to be disastrous over more than a day or two. They either heated too much or not enough and temperature fluctuations are VERY hard on bettas. This heater has been awesome, with one caveat. In order for this--or really any heater--to be effective, you must have adequate water circulation in your tank. This is a problem for betta parents because bettas do not do well with a lot of turbulence. The water coming out of our filter is baffled, so the water in the tank does not move around the heater on its own. This results in the heater turning on and off frequently and the tank getting cold because the thermostat is being "tricked" by the warm water just sitting around the heater. However, we found that a micro-bubble air stone placed about an inch from the heater, and running at at least 75% capacity, keeps enough water moving around the heater for it to be spot-on accurate at keeping the entire tank at the selected temperature. And our betta is not bothered at all by the tiny bubbles. We actually added a second stone on the opposite side of the tank as well, and I think that makes it even better, but having one near the heater is the most important. With this setup, our tank stays at a perfect, consistent 79.5 degrees. Love it!

I really like this product it keeps its temperature accuracy I'm really happy with it it does a very good job

In general, a good quality product, but only for about a year. I've purchased four of these over the last few years, and it's the same story with all but one - 'Used them constantly in the cold months (about 5 mos), then stored them during the warm months. When cold weather came back around, they might heat up or might not... If not, I'd buy a new replacement. I finally decided to contact the company to see how valid their advertised "lifetime warranty" is.Update:Good news - I contacted the company about warranties and to seek technical advice to see if I was doing anything wrong. Turns out I'd been over-working the heaters, shortening their service life, and will make changes to keep things more realistic. The best part is the company stands behind their product and is working on replacing my broken heaters, under warranty. I'll be sticking with these Aqueon heaters in the future, for sure

Updated 7/4- This heater worked great for 2 months before the temperature kept dropping even though I was increasing the temperature setting. I have never changed the water in my tank without unplugging it and the water level never got low. This was an expensive heater and although I know they don't last forever, I expected more than 2 months of use. Thankfully, I had a back heater on hand.I purchased 3 heaters before this one and I wasn't happy with any of them. One got way too hot to be safe, another didn't keep the temperature consistent. This one is perfect. The temperature is always exactly the same. I'm using this for a 5 gallon aquarium with a Betta.

This aquarium heater is accurate right out of the box, no adjustments needed. It keeps the temp in my 5 gallon aquarium steady. Heats gently, comes on when needed, but doesn't cycle on and off constantly. Very well made.It wasn't easy to find an adjustable heater which would fit in a nano tank. Since it is my hospital tank, I needed the option to increase the temperature for certain medications. One smaller, adjustable unit that I got for it was erratically inaccurate in the temperature it maintained (or didn't) and completely failed to function in 31 days. This Aqueon has been quality and steady as a rock from the beginning. I'd buy it again!

Bought it December 2022, worked ok but the light was difficult to see whether it was on or not, plus the suction cups and bracket refused to stay stuck on the tank. Unplugged it for the summer months, and now it's not working when I need it again. I'm ordering a Fluval brand, hopefully it lasts more than a few months.

Bought this heater as a replacement. My last aqueon heater of the same model lasted 4 years. They say most heaters last 2 to 3 years so have high hopes this one will last just as long. It maintains a steady temperature and is easy to adjust.

I’ve owned this heater since 2019 and still going strong….Just ordered a second as a back up if this eventually goes out!Holds a consistent temperature and love that it is submersible and not glass.Highly recommend this heater!

Good quality in workmanship. Works perfectly for my 77 gallon tank.

buen articulo. mal empaquetado, (muy fragil), llegó el empaque aplastado.

Great product overall, very reputable name. Best price found on Amazon. Easy to install and a fix to your aquarium. Very quiet heater with easily seen light to detect when on or off.

Pésimo producto, no duro mas de 3 meses y la garantía solo sirve para USA y Canada. El calentador dejo de reconocer que el agua no estaba a la temperatura correcta y dejo de calentar.

I bought this because of the slim profile and black colour, but after having the second one of these fail in a two year period, I’m going back to trusty Eheim heaters. This is a great looking heater, but I need a heater that I can count on to maintain the temperature in the aquarium.