AqueonAdjustable PRO Aquarium Heater Up to 20 Gallons, 50 Watts

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!

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.

I’ve been using this heater in my turtle tank for 8 months and it’s still going strong. The one I had before lasted for about three years before I had to purchase this one. The temperature control is accurate, within one degree Fahrenheit.

I bought this for my aquatic turtle, when I was upgrading her tank. The suction is less than optimal, but it still works when it's only half attached to the wall. Keeps the water within a few degrees either way from the setting, which is fine. It does seem to be less effective with better water circulation, though, so consider one on each end of the tank if you have a strong filter.

I've used every brand of aquarium heaters & every amount of wattage during my >45 years of having many aquariums, & when any heater stopped functioning I wrote down that brand & what happened. discovered ALL brands of aquarium heaters eventually failed, even Aqueon. But Aqueon brand heaters lasted longer than all other brands. Aqueon's PRO heaters are outrageously expensive, the difference being their "PRO" heaters have metal outer tube insteadof glass tube. Aqueon regular (non-Pro) heaters & other brands have glass outer tubes which eventually crack & leak regardless how careful you are. I pay for this metal tube because that's 1 less part of a heater to go bad.

They were purchased as green house plant tower water reservoir heaters. This is the brand they recommended. They MUST be mounted vertical or horizontal. The top must always be higher then the bottom., otherwise unit will not work.

This is a convenient and fairly inexpensive aquarium heater. It works like you want, and is calibrated but I wouldn't rely on the dial since you really care about the entire tank temperature not necessarily the temp right at the heater. I would recommend another thermometer that is more mid-tank if you are particular about the exact temperature. Also, as I said in the title, the last one of these units simply failed to heat after a couple of years. I assume there is an element that can either burn out or be damaged by rough handling. It is impossible to disassemble to inspect it. I don't know that we were particularly rough on it but it is common to pull it out and let it hang down while you are cleaning, etc. Perhaps it smacked the side of the table or something. I'm not implying that it was defective, just that it isn't what I would call a ruggedized product. Treat it like any electrical appliance. It looks nice and sturdy, but don't abuse it.

I waited a few months to write this review as I have had HORRIBLE luck with tank heaters made by other brands.I will say that when it comes to in the tank heaters, this is one product where you get what you pay for. So it is well worth spending the extra money on one. If you cheap out, you run the risk of killing your fish. Trust me, I speak from experience. Lost a whole tank of expensive fish that I personally bred due to a different brand that stuck on and cooked my tankSo, on to this heater.It is very well made. It just feels solid and well built.It DID take me a couple of days of adjusting to get it to the temp I needed. Don’t rely on the dial on the heater. It’s not going to help. They aren’t accurate.But, once I got it dialed in, I have had zero issues and haven’t had to adjust it since.I will be needing another heater soon and will be buying a second one of these so that is my review in a nutshell.

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

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.

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

Heater is not operating correctly. LED Stays red at all times. Never goes green to indicate correct Temp has been reached. It is in a 5 gallon betta Tank. I put a Thermometer in the tank and set the heater to 85. Its been like that for 30days and seems to hold 75 degrees ish. +-2 degrees. Pretty disappointment as I have always used a well know German Brand and tried a change. This was expensive and top of the Aqueon Heater line. Even though its only a 5 gallon, I take this little Nano Tank Seriously.

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.